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Miscellaneous_Word_Problems/203188: How many points in the first quadrant satisfy both of the
following conditions: (i) the x and y coordinates are positive
integers and (ii) x + y ≤ 5?
1 solutions

Answer 153301 by jim_thompson5910(28595) About Me  on 2009-07-15 17:32:35 (Show Source):
You can put this solution on YOUR website!
Since "x" and "y" are both positive integers (ie positive whole numbers 1, 2, 3, 4, etc...) just ask yourself: "what two numbers add to another number that is either less than or equal to 5?"

So for instance, 2+2=4 which is less than or equal to 5. Also, 1+2=3 which is also less than or equal to 5. Furthermore, 2+3=5 which is less than or equal to 5.

These values can be thought of as the ordered pairs (2,2), (1,2), and (2,3)



Here are all of the possible ordered pairs

(0, 0),
(0, 1),
(0, 2),
(0, 3),
(0, 4),
(0, 5),
(1, 0),
(1, 1),
(1, 2),
(1, 3),
(1, 4),
(2, 0),
(2, 1),
(2, 2),
(2, 3),
(3, 0),
(3, 1),
(3, 2),
(4, 0),
(4, 1),
(5, 0)


So for example, the ordered pair (1,4) means that 1+4=5 which is less than or equal to 5.


Square-cubic-other-roots/203195: I need help rationalizing....
9 times the cubic root 2 over/divided by the cubic root 5 minus cubic root 2.
Please help! Soory my keyboard will not allow me to type the equation.
1 solutions

Answer 153300 by jim_thompson5910(28595) About Me  on 2009-07-15 17:23:25 (Show Source):
You can put this solution on YOUR website!
%289%2Aroot%283%2C2%29%29%2F%28root%283%2C5%29-root%283%2C2%29%29 Start with the given expression.


Let x=root%283%2C5%29 and y=root%283%2C2%29


%289%2Ay%29%2F%28x-y%29 Replace each root%283%2C5%29 with "x" and each root%283%2C2%29 with "y"


Now this is where you have to get a bit creative. It's very helpful to remember that x%5E3-y%5E3=%28x-y%29%28x%5E2%2Bxy%2By%5E2%29. Why is this important? Because if you cube a cube root, they will both cancel out (leaving the stuff inside as a remainder).

So if we multiply both numerator and denominator by x%5E2%2Bxy%2By%5E2, we get:


%289%2Ay%28x%5E2%2Bxy%2By%5E2%29%29%2F%28%28x-y%29%28x%5E2%2Bxy%2By%5E2%29%29


%289%2Ay%28x%5E2%2Bxy%2By%5E2%29%29%2F%28x%5E3-y%5E3%29 Use the identity given above


Plug in x=root%283%2C5%29 and y=root%283%2C2%29


Cube the cube roots (to eliminate them)


Subtract


Reduce


Combine the roots.


Multiply


3%2Aroot%283%2C2%29%28root%283%2C5%5E2%29%2Broot%283%2C10%29%2Broot%283%2C2%5E2%29%29 Use the identity %28root%28n%2Cx%29%29%5Em=root%28n%2Cx%5Em%29


3%2Aroot%283%2C2%29%28root%283%2C25%29%2Broot%283%2C10%29%2Broot%283%2C4%29%29 Square 5 to get 25 and square 2 to get 4


Distribute


3%2Aroot%283%2C2%2A25%29%2B3%2Aroot%283%2C2%2A10%29%2B3%2Aroot%283%2C2%2A4%29 Combine the roots.


3%2Aroot%283%2C50%29%2B3%2Aroot%283%2C20%29%2B3%2Aroot%283%2C8%29 Multiply


==================================================================

Answer:


So


This can be verified (as I have verified it myself) with a calculator.


Trigonometry-basics/203109: i was wondering how you do these problems: The directions are to find the exact value of each expression.
6 cos 3π/4+ 2tan(-π/3)
and
sec ( -π/3)- cot (-5π/4)
please i am struggling to do this work. I would appreciate if you would explain in detail. Thank you in advance.
1 solutions

Answer 153249 by jim_thompson5910(28595) About Me  on 2009-07-14 23:48:19 (Show Source):
You can put this solution on YOUR website!
Ok, first off let's bring up the unit circle




This is a very handy tool. For each given angle (located on the spokes of the wheel), there is a point that lies on the circle. It turns out that the x coordinate of the point refers to the cosine of that given angle. Likewise, the y coordinate of the point refers to the sine of that angle.

For example, the cosine of pi%2F3 is cos%28pi%2F3%29=1%2F2 since the x coordinate of this point is x=1%2F2. Also, the sine of pi%2F3 is sin%28pi%2F3%29=sqrt%282%29%2F2 since the y coordinate of this point is y=sqrt%282%29%2F2. You can use the unit circle to evaluate the sine/cosine of any given angle shown.


Finally, remember that we have the following identities:

tan%28x%29=sin%28x%29%2Fcos%28x%29

sec%28x%29=1%2Fcos%28x%29

cot%28x%29=1%2Ftan%28x%29=cos%28x%29%2Fsin%28x%29



I hope this will refresh something or help you get started. If this didn't help, please let me know or repost.


Money_Word_Problems/203103: Debbie plans on investing enough money so that she will have $2000 at the end of two years. How much money wll she have to invest now if her money will grow according to the followning formula: 2000=P(1.025)^4?
When I work this problem I seem to come up with 0=0
2000=P(1.025)^4
1.025^4=1.103812891
I don't understand.
1 solutions

Answer 153235 by jim_thompson5910(28595) About Me  on 2009-07-14 19:56:30 (Show Source):
You can put this solution on YOUR website!
I'm assuming that you have the correct formula...



2000=P%281.025%29%5E4 Start with the given equation.


2000=P%281.103812%29 Raise 1.025 to the 4th power to get 1.103812


2000%2F1.103812=P Divide both sides by 1.103812 to isolate "P".


1811.902=P Divide


P=1811.90 Rearrange the equation and round to the nearest hundredth (ie to the nearest penny).



So she needs to invest $1,811.90


Radicals/203101: This question is from textbook
{{cube root of 108x^3y^7/2y^3}}
1 solutions

Answer 153233 by jim_thompson5910(28595) About Me  on 2009-07-14 19:38:04 (Show Source):
You can put this solution on YOUR website!
root%283%2C%28108x%5E3y%5E7%29%2F%282y%5E3%29%29 Start with the given expression.


root%283%2C%2854x%5E3y%5E7%29%2F%28y%5E3%29%29 Reduce the coefficients.


root%283%2C54x%5E3y%5E%287-3%29%29 Divide the common variable terms by subtracting the exponents.


root%283%2C54x%5E3y%5E4%29 Subtract


root%283%2C27%2A2x%5E3y%5E4%29 Factor 54 into 27*2


root%283%2C27%2A2x%5E3y%5E3%2Ay%29 Factor y%5E4 into y%5E3%2Ay


Break up the root.


3%2Aroot%283%2C2%29%2Aroot%283%2Cx%5E3%29%2Aroot%283%2Cy%5E3%29%2Aroot%283%2Cy%29 Take the cube root of 27 to get 3


3%2Aroot%283%2C2%29%2Ax%2Aroot%283%2Cy%5E3%29%2Aroot%283%2Cy%29 Take the cube root of x%5E3 to get "x"


3%2Aroot%283%2C2%29%2Ax%2Ay%2Aroot%283%2Cy%29 Take the cube root of y%5E3 to get "y"


3xy%2Aroot%283%2C2y%29 Rearrange the terms and combine the roots.


So root%283%2C%28108x%5E3y%5E7%29%2F%282y%5E3%29%29=3xy%2Aroot%283%2C2y%29 where y%3C%3E0


Complex_Numbers/203100: This question is from textbook
Imaginary numbers

x^2-2x+12,x=1-2i
1 solutions

Answer 153231 by jim_thompson5910(28595) About Me  on 2009-07-14 19:31:26 (Show Source):
You can put this solution on YOUR website!
x%5E2-2x%2B12 Start with the given expression.


%281-2i%29%5E2-2%281-2i%29%2B12 Plug in x=1-2i


1-4i%2B4i%5E2-2%281-2i%29%2B12 FOIL


1-4i%2B4i%5E2-2%2B4i%2B12 Distribute


11%2B4i%5E2 Combine like terms.


11%2B4%28-1%29 Plug in i%5E2=-1


11-4 Multiply


7 Subtract


So %281-2i%29%5E2-2%281-2i%29%2B12=7


This means that x%5E2-2x%2B12=7 when x=1-2i


Graphs/203102: #1
What is the slope of the line containing the points (-1,4) and (3,2)?
a. -2
b. 1/2
c. -1/2
d. 2


--------------------------------------------------------------------------------

Question 2 (Multiple Choice Worth 1 points)
Choose the best description for graphing the point (3,-4).
a. Go to the left three and up four.
b. Go to the right three and up four.
c. Go to the right three and down four.
d. Go to the left three and down four.


--------------------------------------------------------------------------------

Question 3 (Multiple Choice Worth 1 points)
Put the following equation in slope intercept form 2x - 5y = 10.
a. x-y = (-2/5)x-2
b. y = (-2/5)x + 2
c. y = -2x + 10
d. y = (2/5)x -2


--------------------------------------------------------------------------------

Question 4 (Multiple Choice Worth 1 points)
What is the slope of the line with equation y = (1/2)x -3?
a. 1/2
b. -3
c. 2
d. -2


--------------------------------------------------------------------------------

Question 5 (Multiple Choice Worth 1 points)
In the equation y=-2x +5, name the slope and the y intercept.
a. slope 1/2, y intercept 5
b.slope -2, y intercept 5
c.slope 5, y intercept -2
d. slope 5, y intercept 1/2


--------------------------------------------------------------------------------

Question 6 (Multiple Choice Worth 1 points)
What is the y intercept of the equation y= (2/3)x -6?
a. 2/3
b. 6
c. -6
d.No y intercept


--------------------------------------------------------------------------------

Question 7 (Multiple Choice Worth 1 points)
Choose the best directions for graphing the equation y= (1/2)x + 1.
a. Graph the point (0,1) and count up 1 and to the right 2 to find another point on the line.
b. Graph the point (1,0) and count up 1 and to the right 2 to find another point on the line.
c. Graph the point (0,1) and count to the right 1 and up 2 to find another point on the line.
d. Graph the point (1,0) and count to the right 1 and up 2 to find another point on the line.


--------------------------------------------------------------------------------

Question 8 (Multiple Choice Worth 1 points)
What kind of line is created when you graph the equation x=2?
a.Horizontal line
b.Oblique line
c.Vertical line
d.No line is created.


--------------------------------------------------------------------------------

Question 9 (Multiple Choice Worth 1 points)
What is the slope of the line x=2?
a.Zero
b.Undefined
c.2
d.Not enough information.


--------------------------------------------------------------------------------

Question 10 (Multiple Choice Worth 1 points)
What is the slope of the line y= -3?
a.Zero
b.Undefined
c.-3
d.Not enough information.


--------------------------------------------------------------------------------

Question 11 (Multiple Choice Worth 1 points)
Choose the equation that is written in standard form.
a.y= -3x +4
b.2y = x+8
c.x = 3y-6
d.4x -2y = 10


--------------------------------------------------------------------------------

Question 12 (Multiple Choice Worth 1 points)
Find the x intercept of the graph represented by the equation 3x + 4y = 12.
a.(0,3)
b.(3,0)
c.(4,0)
d.(0,4)


--------------------------------------------------------------------------------

Question 13 (Multiple Choice Worth 1 points)
Find the y intercept of the graph represented by the equation 3x + 4y = 12.
a.(0,3)
b.(3,0)
c.(4,0)
d.(0,4)


--------------------------------------------------------------------------------

Question 14 (Multiple Choice Worth 1 points)
Choose ALL the points that are solutions to the equation y= 2x -5.
a.(0,-5)
b.(1,3)
c.(-1,-7)
d.(1/2, -4)


--------------------------------------------------------------------------------

Question 15 (Multiple Choice Worth 1 points)
Choose the equation of the line with a slope of 2/3 and y passing through the point (6,-2).
a.y= (2/3)x -6
b.y= (2/3)x -2
c.y= (2/3) x -4
d.y = (3/2) x -6


--------------------------------------------------------------------------------

Question 16 (Multiple Choice Worth 1 points)
Choose the equation of the line passing through the points (-2,3) and (-4,1).
a.y = x -1
b.y = (-1/3)x + 7/3
c.y= x-4
d.y = x + 5


--------------------------------------------------------------------------------

Question 17 (Multiple Choice Worth 1 points)
Choose the equation of the vertical line passing through the point (-2,1).
a.x = -2
b.x = 1
c.y = -2
d.y = 1


--------------------------------------------------------------------------------

Question 18 (Multiple Choice Worth 1 points)
Choose the equation of the line passing through the points (3,4) and (1,-6).
a.y = 5x - 19
b.y = (1/5)x + 15/5
c.y = (1/5)x - 2
d.y = 5x - 11


--------------------------------------------------------------------------------

Question 19 (Multiple Choice Worth 1 points)
Choose the ordered pair that is the solution to the following system of equations: y= 2x + 1 and y = x -5.
a.(-6, -1)
b.(-6,-11)
c.(4,9)
d.(4,-1)


--------------------------------------------------------------------------------

Question 20 (Multiple Choice Worth 1 points)
Choose the orderred pair that is the solution to the following system of equations: -3x + y = 4 and -7x + y = 12.
a.(-2,-2)
b.(-2,2)
c.(2,-2)
d.(2,2)


--------------------------------------------------------------------------------

Question 21 (Multiple Choice Worth 1 points)
Choose the ordered pair that is the solution to the following system of equations: 5x - 2y = 3 and 3x + 4y = 7.
a.(1,-1)
b.(-1,1)
c.(-1,-1)
d.(1,1)


--------------------------------------------------------------------------------

Question 22 (Essay Worth 1 points)
Give an ordered pair that is the solution to the equation y = 5x + 2.




--------------------------------------------------------------------------------

Question 23 (Multiple Choice Worth 1 points)
Choose the equation of the line that is perpendicular to the line shown in the graph and passes through the point shown in the graph.


a.y = x - ll
b.y= 3x – 11
c.y = -3x - 11
d.y = -x + 11


--------------------------------------------------------------------------------

Question 24 (Multiple Choice Worth 1 points)
Choose the equation of the line that is perpendicular to the line shown in the graph and passes through the point shown in the graph.


a.y = 2x + 7

b.y = -2x + 10
c.y = 2x - 10


--------------------------------------------------------------------------------

Question 25 (Multiple Choice Worth 1 points)
The figure shown below looks like a trapezoid. By definition, a trapezoid is a four-sided figure with at least two parallel sides. Choose the best description below of how to determine whether the figure shown is or is not a trapezoid.


a.Find the slope of the line between point (-9,5) and point (-3,8). Then find the slope of the line between point (4,-1) and point (3,5). If the slopes are opposite reciprocals, then the figure is a trapezoid.
b.Find the slope of the line between point (-3,8) and point (3,5). Then find the slope of the line between point (-9,5) and point (4,-1). If the slopes are the same, then the figure is a trapezoid.
c.Find the slope of the line between point (-9,5) and point (3,5). Then find the slope of the line between point (-3,8) and point (4,-1). If the slopes are the same, then the figure is a trapezoid.
d.Find the slope of the line between point (-3,8) and point (3,5). Then find the slope of the line between point (-9,5) and point (4,-1). If the slopes are opposite reciprocals, then the figure is a trapezoid.

1 solutions

Answer 153229 by jim_thompson5910(28595) About Me  on 2009-07-14 19:23:05 (Show Source):
You can put this solution on YOUR website!
We're not here to do your homework. If that's the case, you might as well give us your degree, your job, and any money that you make from it. Not much fun is it? If you are struggling with the problems, please break them up and show that you've attempted to solve them. Also, post the problems that are giving you the most trouble.


Travel_Word_Problems/203094: Can you please help me write out and solve the equation for this word problem?
A car leaves a town traveling at 60 miles per hour. How long will it take a second car traveling at 75 miles per hour to catch up to the first car if it leaves 2 hours later?

1 solutions

Answer 153227 by jim_thompson5910(28595) About Me  on 2009-07-14 18:17:27 (Show Source):
You can put this solution on YOUR website!
Let's make t = time (in hours) that the first car travels.


First, let's set up the equation for the first car to leave. Recall that the distance "d" equals the speed "r" multiplied by the time "t". So this means that


d=rt


d=60t Plug in r=60 (the speed of the first car)


-------------

Now let's set up the second equation (for the second car). Since the first car travels "t" hours, and it has a 2 hour head start, this means that the second car is going to travel "t-2" hours (eg, the first car travels t=6 hours and the second travels t-2=6-2=4 hours).


So this means that we start with d=rt and plug in r=75 and replace "t" with "t-2" to get d=75%28t-2%29


Note: the "d"s of both equations are the same "d" since the cars will have gone the distance when they meet.


So we have the two equations d=60t and d=75%28t-2%29


d=60t Start with the first equation.


75%28t-2%29=60t Plug in d=75%28t-2%29


75t-150=60t Distribute.


75t=60t%2B150 Add 150 to both sides.


75t-60t=150 Subtract 60t from both sides.


15t=150 Combine like terms on the left side.


t=%28150%29%2F%2815%29 Divide both sides by 15 to isolate t.


t=10 Reduce.


----------------------------------------------------------------------

Answer:

So the solution is t=10 which means that the first car traveled for 10 hours


Subtract 2 from this answer to get 10-2=8. So this tells us that the second car traveled 8 hours.


So it takes 8 hours for the second car to catch up and meet the first car.


Linear-systems/203093: 1.Use the Substitution method to solve the system of equations.
x + y = 10
y = x + 8
2.Use the Substitution method to solve the system of equations.
3x + y = 5
4x - 7y = -10
3.Use the Substitution method to solve the system of equations.
y - 2x = -5
3y - x = 5

can you please help me solve each step by step so i can under stand
1 solutions

Answer 153222 by jim_thompson5910(28595) About Me  on 2009-07-14 17:31:26 (Show Source):
You can put this solution on YOUR website!
# 1


Start with the given system of equations:


system%28x%2By=10%2Cy=x%2B8%29


y=x%2B8 Start with the second equation.


-------------------------------------------


x%2By=10 Move onto the first equation.


x%2Bx%2B8=10 Plug in y=x%2B8.


2x%2B8=10 Combine like terms on the left side.


2x=10-8 Subtract 8 from both sides.


2x=2 Combine like terms on the right side.


x=%282%29%2F%282%29 Divide both sides by 2 to isolate x.


x=1 Reduce.


-------------------------------------------


Since we know that x=1, we can use this to find y.


y=x%2B8 Go back to the second equation.


y=1%2B8 Plug in x=1.


y=9 Add


So the solutions are x=1 and y=9.


This means that the system is consistent and independent.


Notice when we graph the equations, we see that they intersect at . So this visually verifies our answer.


Graph of x%2By=10 (red) and y=x%2B8 (green)





# 2



Start with the given system of equations:


system%283x%2By=5%2C4x-7y=-10%29


3x%2By=5 Start with the first equation.


y=5-3x Subtract 3x from both sides.


y=-3x%2B5 Rearrange the terms and simplify.


-------------------------------------------


4x-7y=-10 Move onto the second equation.


4x-7%28-3x%2B5%29=-10 Now plug in y=-3x%2B5.


4x%2B21x-35=-10 Distribute.


25x-35=-10 Combine like terms on the left side.


25x=-10%2B35 Add 35 to both sides.


25x=25 Combine like terms on the right side.


x=%2825%29%2F%2825%29 Divide both sides by 25 to isolate x.


x=1 Reduce.


-------------------------------------------


Since we know that x=1, we can use this to find y.


3x%2By=5 Go back to the first equation.


3%281%29%2By=5 Plug in x=1.


3%2By=5 Multiply.


y=5-3 Subtract 3 from both sides.


y=2 Combine like terms on the right side.


So the solutions are x=1 and y=2.


This means that the system is consistent and independent.


Notice when we graph the equations, we see that they intersect at . So this visually verifies our answer.


Graph of 3x%2By=5 (red) and 4x-7y=-10 (green)





# 3



Start with the given system of equations:


system%28-2x%2By=-5%2C-x%2B3y=5%29


-2x%2By=-5 Start with the first equation.


y=-5%2B2x Add 2x to both sides.


y=2x-5 Rearrange the terms and simplify.


-------------------------------------------


-x%2B3y=5 Move onto the second equation.


-x%2B3%282x-5%29=5 Now plug in y=2x-5.


-x%2B6x-15=5 Distribute.


5x-15=5 Combine like terms on the left side.


5x=5%2B15 Add 15 to both sides.


5x=20 Combine like terms on the right side.


x=%2820%29%2F%285%29 Divide both sides by 5 to isolate x.


x=4 Reduce.


-------------------------------------------


Since we know that x=4, we can use this to find y.


-2x%2By=-5 Go back to the first equation.


-2%284%29%2By=-5 Plug in x=4.


-8%2By=-5 Multiply.


y=-5%2B8 Add 8 to both sides.


y=3 Combine like terms on the right side.


So the solutions are x=4 and y=3.


This means that the system is consistent and independent.


Notice when we graph the equations, we see that they intersect at . So this visually verifies our answer.


Graph of -2x%2By=-5 (red) and -x%2B3y=5 (green)


Exponential-and-logarithmic-functions/203087: Find the absolute maximum and absolute minimum values of the function below. If an absolute maximum or minimum does not exist, enter NONE.
f(x) = x^2 + 250/x on the open interval (0,infinity )
I know that the absolute max is the answer NONE
but I can not figure out the absolute min
can someone help please
thanks
1 solutions

Answer 153219 by jim_thompson5910(28595) About Me  on 2009-07-14 16:28:18 (Show Source):
You can put this solution on YOUR website!
Here are the basics to finding the extrema (ie the max/min)

Step 1) Derive the function f(x) to get f'(x)

Since this means that or simply


Step 2) Set the derivative function f'(x) equal to zero





Multiply both sides by x%5E2 and rearrange the equation.


Add 250 to both sides.


Take the square root of both sides


Simplify the square root


Evaluate the square root


Now because the domain is , this means that we must reject x=-15.8114 (as it isn't in the domain)


So the max/min occurs at the approximate value x=15.8114 (or at the endpoints)


Now if you graph the function (or evaluate a list of x values), you'll find that there is no max value (so you are correct). So this means that the min occurs when x=15.8114 or the min occurs at the endpoints of the interval. Because x=0 is not defined (and infinity is not a number), this means that the min must occur at x=15.8114


Step 3) Find the minimum value of the function f(x)

From here, simply plug in the x value that generates the min value, which in this case is x=15.8114 to get






So the absolute min is approximately f(x)=31.6228 and occurs at x=15.8114


Note: if you want to keep things exact, then you can plug in x=5%2Asqrt%2810%29 to get the min value: . This would then mean that the absolute min of f%28x%29=10%2Asqrt%2810%29 occurs at x=5%2Asqrt%2810%29


Pythagorean-theorem/203082: the sum of two numbers is 12. their product is 32. find the numbers.
not good at word problem so i am have trouble setting it up. once i get it set up i can work its just braking it down to set it up. please help.
1 solutions

Answer 153199 by jim_thompson5910(28595) About Me  on 2009-07-14 14:29:05 (Show Source):
You can put this solution on YOUR website!
Let

x = first number
y = second number


"the sum of two numbers is 12" translates to x%2By=12

and "their product is 32" means that xy=32


So you basically have the system


system%28x%2By=12%2Cxy=32%29


I'll let you take it from there. Let me know if you need more help.


Linear-systems/203073: -3x+y=3 and 2x-y=-1
what is the solution
1 solutions

Answer 153190 by jim_thompson5910(28595) About Me  on 2009-07-14 13:27:04 (Show Source):
You can put this solution on YOUR website!

Start with the given system of equations:


system%28-3x%2By=3%2C2x-y=-1%29


-3x%2By=3 Start with the first equation.


y=3%2B3x Add 3x to both sides.


y=3x%2B3 Rearrange the terms and simplify.


-------------------------------------------


2x-y=-1 Move onto the second equation.


2x-%283x%2B3%29=-1 Now plug in y=3x%2B3.


2x-3x-3=-1 Distribute.


-x-3=-1 Combine like terms on the left side.


-x=-1%2B3 Add 3 to both sides.


-x=2 Combine like terms on the right side.


x=%282%29%2F%28-1%29 Divide both sides by -1 to isolate x.


x=-2 Reduce.


-------------------------------------------


Since we know that x=-2, we can use this to find y.


-3x%2By=3 Go back to the first equation.


-3%28-2%29%2By=3 Plug in x=-2.


6%2By=3 Multiply.


y=3-6 Subtract 6 from both sides.


y=-3 Combine like terms on the right side.


So the solutions are x=-2 and y=-3.


This means that the system is consistent and independent.


Notice when we graph the equations, we see that they intersect at . So this visually verifies our answer.


Graph of -3x%2By=3 (red) and 2x-y=-1 (green)


Polynomials-and-rational-expressions/203062: I have to perform the operation of:

k^2+3k-10      3
_________ x ________
    36       k^2-4


I tried to look for simplification by factoring out the first numerator to (k+5)(k-2). But I don't see how I can factor out a (k-2) from the second denominator because there's no k value in the expression. However, the choices for answers indicate that it is cancelled out somehow. Where do I go from here?
1 solutions

Answer 153184 by jim_thompson5910(28595) About Me  on 2009-07-14 13:01:45 (Show Source):
You can put this solution on YOUR website!
%28%28k%5E2%2B3k-10%29%2F36%29%283%2F%28k%5E2-4%29%29 Start with the given expression.


%28%28%28k%2B5%29%28k-2%29%29%2F36%29%283%2F%28k%5E2-4%29%29 Factor the first numerator


%28%28%28k%2B5%29%28k-2%29%29%2F%2812%2A3%29%29%283%2F%28k%5E2-4%29%29 Factor the first denominator


%28%28%28k%2B5%29%28k-2%29%29%2F%2812%2A3%29%29%283%2F%28%28k-2%29%28k%2B2%29%29%29 Factor the second denominator (hint: use the difference of squares formula)


%283%28k%2B5%29%28k-2%29%29%2F%2812%2A3%28k-2%29%28k%2B2%29%29 Combine the fractions.


Highlight the common terms.


Cancel out the common terms.


%28k%2B5%29%2F%2812%28k%2B2%29%29 Simplify


%28k%2B5%29%2F%2812k%2B24%29 Distribute



So %28%28k%5E2%2B3k-10%29%2F36%29%283%2F%28k%5E2-4%29%29 simplifies to %28k%2B5%29%2F%2812k%2B24%29


In other words, %28%28k%5E2%2B3k-10%29%2F36%29%283%2F%28k%5E2-4%29%29=%28k%2B5%29%2F%2812k%2B24%29


Polynomials-and-rational-expressions/203065: (n^2+5n+6/n^2+7n+12)(n^2+9n+20/n^2+11n+30)= ?
1 solutions

Answer 153181 by jim_thompson5910(28595) About Me  on 2009-07-14 12:37:08 (Show Source):
You can put this solution on YOUR website!

Start with the given expression.


Factor n%5E2%2B5n%2B6 to get %28n%2B3%29%28n%2B2%29.


Factor n%5E2%2B7n%2B12 to get %28n%2B4%29%28n%2B3%29.


Factor n%5E2%2B9n%2B20 to get %28n%2B5%29%28n%2B4%29.


Factor n%5E2%2B11n%2B30 to get %28n%2B6%29%28n%2B5%29.


Combine the fractions.


Highlight the common terms.


Cancel out the common terms.


%28n%2B2%29%2F%28n%2B6%29 Simplify.


So simplifies to %28n%2B2%29%2F%28n%2B6%29.


In other words,


Polynomials-and-rational-expressions/203014: (3x^2 + 4x – 3) + (2x^2 – 3x -1) – (x^2 + x + 7)
I just do not get this. I do not understand any algebra at all. It might as well be Chineese. I am in my 5th week of 10 and am failing. I need to pass this class. I need ti understand. The light just won't go on?
Please help, Angela
1 solutions

Answer 153155 by jim_thompson5910(28595) About Me  on 2009-07-13 23:13:04 (Show Source):
You can put this solution on YOUR website!
When we want to add two variable expressions like "x" and "2x", what we're really doing is adding the coefficients. So x+2x=3x. Remember "2x" is the same as "x+x". So x+2x=x+x+x=3x


%283x%5E2+%2B+4x+-+3%29+%2B+%282x%5E2+-+3x+-1%29+-+%28x%5E2+%2B+x+%2B+7%29+ Start with the given expression.


3x%5E2+%2B+4x+-+3+%2B+2x%5E2+-+3x+-1+-+x%5E2+-+x+-+7+ Distribute


%283x%5E2%2B+2x%5E2-+x%5E2%29+%2B+%284x-+3x-+x%29%2B%28-+3+-1+-+7%29+ Group like terms.


4x%5E2+-+11+ Combine like terms.


So %283x%5E2+%2B+4x+-+3%29+%2B+%282x%5E2+-+3x+-1%29+-+%28x%5E2+%2B+x+%2B+7%29=4x%5E2+-+11+


Equations/202989: 3-(x/3)=2x/5
This is actually a rational equation but i couldn't find it in the topics.
1 solutions

Answer 153142 by jim_thompson5910(28595) About Me  on 2009-07-13 19:49:10 (Show Source):
You can put this solution on YOUR website!

3-x%2F3=2x%2F5 Start with the given equation.


15%283%29-cross%2815%29%5E5%28x%2Fcross%283%29%29=15%282x%2Fcross%285%29%29 Multiply EVERY term by the LCD 15 to clear any fractions.


45-5x=6x Multiply and simplify.


-5x=6x-45 Subtract 45 from both sides.


-5x-6x=-45 Subtract 6x from both sides.


-11x=-45 Combine like terms on the left side.


x=%28-45%29%2F%28-11%29 Divide both sides by -11 to isolate x.


x=45%2F11 Reduce.


----------------------------------------------------------------------

Answer:

So the solution is x=45%2F11 which approximates to x=4.091.


Graphs/202967: What is an equation of the points on the graph(0,5) and (1,1) ?
1 solutions

Answer 153106 by jim_thompson5910(28595) About Me  on 2009-07-13 15:27:21 (Show Source):
You can put this solution on YOUR website!

First let's find the slope of the line through the points and


Note: is the first point . So this means that x%5B1%5D=0 and y%5B1%5D=5.
Also, is the second point . So this means that x%5B2%5D=1 and y%5B2%5D=1.


m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29 Start with the slope formula.


m=%281-5%29%2F%281-0%29 Plug in y%5B2%5D=1, y%5B1%5D=5, x%5B2%5D=1, and x%5B1%5D=0


m=%28-4%29%2F%281-0%29 Subtract 5 from 1 to get -4


m=%28-4%29%2F%281%29 Subtract 0 from 1 to get 1


m=-4 Reduce


So the slope of the line that goes through the points and is m=-4


Now let's use the point slope formula:


y-y%5B1%5D=m%28x-x%5B1%5D%29 Start with the point slope formula


y-5=-4%28x-0%29 Plug in m=-4, x%5B1%5D=0, and y%5B1%5D=5


y-5=-4x%2B-4%28-0%29 Distribute


y-5=-4x%2B0 Multiply


y=-4x%2B0%2B5 Add 5 to both sides.


y=-4x%2B5 Combine like terms.


y=-4x%2B5 Simplify


So the equation that goes through the points and is y=-4x%2B5


Notice how the graph of y=-4x%2B5 goes through the points and . So this visually verifies our answer.
Graph of y=-4x%2B5 through the points and


Linear-systems/202943: Explain how to apply elimination in solving a system of equations; apply substitution in solving a system of equations. Demonstrate each technique in solving the system
2x + 7y = 12
5x - 4y = -13
1 solutions

Answer 153104 by jim_thompson5910(28595) About Me  on 2009-07-13 14:38:43 (Show Source):
You can put this solution on YOUR website!
Start with the given system of equations:


system%282x%2B7y=12%2C5x-4y=-13%29


2x%2B7y=12 Start with the first equation.


7y=12-2x Subtract 2x from both sides.


y=%2812-2x%29%2F%287%29 Divide both sides by 7 to isolate y.


y=-%282%2F7%29x%2B12%2F7 Rearrange the terms and simplify.


-------------------------------------------


5x-4y=-13 Move onto the second equation.


5x-4%28-%282%2F7%29x%2B12%2F7%29=-13 Now plug in y=-%282%2F7%29x%2B12%2F7.


5x%2B%288%2F7%29x-48%2F7=-13 Distribute.


7%285x%2B%288%2Fcross%287%29%29x-48%2Fcross%287%29%29=7%28-13%29 Multiply both sides by the LCD 7 to clear any fractions.


35x%2B8x-48=-91 Distribute and multiply.


43x-48=-91 Combine like terms on the left side.


43x=-91%2B48 Add 48 to both sides.


43x=-43 Combine like terms on the right side.


x=%28-43%29%2F%2843%29 Divide both sides by 43 to isolate x.


x=-1 Reduce.


-------------------------------------------


Since we know that x=-1, we can use this to find y.


2x%2B7y=12 Go back to the first equation.


2%28-1%29%2B7y=12 Plug in x=-1.


-2%2B7y=12 Multiply.


7y=12%2B2 Add 2 to both sides.


7y=14 Combine like terms on the right side.


y=%2814%29%2F%287%29 Divide both sides by 7 to isolate y.


y=2 Reduce.


So the solutions are x=-1 and y=2.


This means that the system is consistent and independent.


Notice when we graph the equations, we see that they intersect at . So this visually verifies our answer.


Graph of 2x%2B7y=12 (red) and 5x-4y=-13 (green)


Polynomials-and-rational-expressions/202948: Factor: 64x^3+27y^3
1 solutions

Answer 153103 by jim_thompson5910(28595) About Me  on 2009-07-13 14:36:27 (Show Source):
You can put this solution on YOUR website!

64x%5E3%2B27y%5E3 Start with the given expression.


%284x%29%5E3%2B%283y%29%5E3 Rewrite 64x%5E3 as %284x%29%5E3. Rewrite 27y%5E3 as %283y%29%5E3.


%284x%2B3y%29%28%284x%29%5E2-%284x%29%283y%29%2B%283y%29%5E2%29 Now factor by using the sum of cubes formula. Remember the sum of cubes formula is A%5E3%2BB%5E3=%28A%2BB%29%28A%5E2-AB%2BB%5E2%29


%284x%2B3y%29%2816x%5E2-12xy%2B9y%5E2%29 Multiply

-----------------------------------
Answer:

So 64x%5E3%2B27y%5E3 factors to %284x%2B3y%29%2816x%5E2-12xy%2B9y%5E2%29.


In other words, 64x%5E3%2B27y%5E3=%284x%2B3y%29%2816x%5E2-12xy%2B9y%5E2%29


Graphs/202960: Could you please help me out?
Find an equation of the line having the given slope and containing the given point. m=7/8, (5,-2)
The equation of the line is y =
Thanks for your help!!
1 solutions

Answer 153102 by jim_thompson5910(28595) About Me  on 2009-07-13 14:34:02 (Show Source):
You can put this solution on YOUR website!

If you want to find the equation of line with a given a slope of 7%2F8 which goes through the point (5, -2), you can simply use the point-slope formula to find the equation:


---Point-Slope Formula---
y-y%5B1%5D=m%28x-x%5B1%5D%29 where m is the slope, and is the given point

So lets use the Point-Slope Formula to find the equation of the line

y--2=%287%2F8%29%28x-5%29 Plug in m=7%2F8, x%5B1%5D=5, and y%5B1%5D=-2 (these values are given)


y%2B2=%287%2F8%29%28x-5%29 Rewrite y--2 as y%2B2


y%2B2=%287%2F8%29x%2B%287%2F8%29%28-5%29 Distribute 7%2F8


y%2B2=%287%2F8%29x-35%2F8 Multiply 7%2F8 and -5 to get -35%2F8


y=%287%2F8%29x-35%2F8-2 Subtract 2 from both sides to isolate y


y=%287%2F8%29x-51%2F8 Combine like terms -35%2F8 and -2 to get -51%2F8 (note: if you need help with combining fractions, check out this solver)


------------------------------------------------------------------------------------------------------------
Answer:


So the equation of the line with a slope of 7%2F8 which goes through the point (5, -2) is:

y=%287%2F8%29x-51%2F8 which is now in y=mx%2Bb form where the slope is m=7%2F8 and the y-intercept is b=-51%2F8


Graphs/202961: I need help with this algebra problem...
Find an equation of the line containing the given pair of points.
(-7,-5) & (-3,-2) in slope intercept form y=
Thank you for your help!!
1 solutions

Answer 153101 by jim_thompson5910(28595) About Me  on 2009-07-13 14:32:00 (Show Source):
You can put this solution on YOUR website!

First let's find the slope of the line through the points and


Note: is the first point . So this means that x%5B1%5D=-7 and y%5B1%5D=-5.
Also, is the second point . So this means that x%5B2%5D=-3 and y%5B2%5D=-2.


m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29 Start with the slope formula.


m=%28-2--5%29%2F%28-3--7%29 Plug in y%5B2%5D=-2, y%5B1%5D=-5, x%5B2%5D=-3, and x%5B1%5D=-7


m=%283%29%2F%28-3--7%29 Subtract -5 from -2 to get 3


m=%283%29%2F%284%29 Subtract -7 from -3 to get 4


So the slope of the line that goes through the points and is m=3%2F4


Now let's use the point slope formula:


y-y%5B1%5D=m%28x-x%5B1%5D%29 Start with the point slope formula


y--5=%283%2F4%29%28x--7%29 Plug in m=3%2F4, x%5B1%5D=-7, and y%5B1%5D=-5


y--5=%283%2F4%29%28x%2B7%29 Rewrite x--7 as x%2B7


y%2B5=%283%2F4%29%28x%2B7%29 Rewrite y--5 as y%2B5


y%2B5=%283%2F4%29x%2B%283%2F4%29%287%29 Distribute


y%2B5=%283%2F4%29x%2B21%2F4 Multiply


y=%283%2F4%29x%2B21%2F4-5 Subtract 5 from both sides.


y=%283%2F4%29x%2B1%2F4 Combine like terms. note: If you need help with fractions, check out this solver.



So the equation that goes through the points and is y=%283%2F4%29x%2B1%2F4


Expressions-with-variables/202957: Please help me solve this equation.
find f(1) for f(x)=2x^3-3x^2+x-21
1 solutions

Answer 153100 by jim_thompson5910(28595) About Me  on 2009-07-13 14:28:45 (Show Source):
You can put this solution on YOUR website!
Note: we're not solving the equation, we're simply plugging in a value for "x" and evaluating.


f%28x%29=2x%5E3-3x%5E2%2Bx-21 Start with the given equation.


f%281%29=2%28red%281%29%29%5E3-3%28red%281%29%29%5E2%2Bred%281%29-21 Plug in x=1.


f%281%29=2%28red%281%29%29-3%281%29%5E2%2B1-21 Cube 1 to get 1.


f%281%29=2%281%29-3%28red%281%29%29%2B1-21 Square 1 to get 1.


f%281%29=red%282%29-3%281%29%2B1-21 Multiply 2 and 1 to get 2.


f%281%29=2-red%283%29%2B1-21 Multiply -3 and 1 to get -3.


f%281%29=red%28-21%29 Combine like terms.


So the answer is f%281%29=-21


Expressions-with-variables/202875: Hi I need help with an area of a trapezoid problem please.
The area of a trapezoid is given by
A=1/2h(a+b)
Solve for a.
Not even sure where to start on this one.
1 solutions

Answer 153033 by jim_thompson5910(28595) About Me  on 2009-07-12 20:54:29 (Show Source):
You can put this solution on YOUR website!
A=%281%2F2%29h%28a%2Bb%29 Start with the given equation.


2A=h%28a%2Bb%29 Multiply both sides by 2.


2A=ha%2Bhb Distribute


2A-hb=ha Subtract hb from both sides.


%282A-hb%29%2Fh=a Divide both sides by "h" to isolate "a".


So the solution is a=%282A-hb%29%2Fh


Radicals/202871: This question is from textbook college algebra
Can you please help me find the solution: +%28-2%2B+radical+-4%292+
Me: (-2+i radical 4)2
Me: (-2)2+2(-2)(i radical 4)+(i radical 4)2
Me: 4-4i radical 4 + 4i(squared)
I know this is wrong...
1 solutions

Answer 153032 by jim_thompson5910(28595) About Me  on 2009-07-12 20:52:10 (Show Source):
You can put this solution on YOUR website!
I'm assuming that the expression is %28-2%2Bsqrt%28-4%29%29%5E2 right????


%28-2%2Bsqrt%28-4%29%29%5E2 Start with the given expression.


%28-2%2Bsqrt%28-1%2A4%29%29%5E2 Factor


%28-2%2Bsqrt%28-1%29%2Asqrt%284%29%29%5E2 Break up the square root.


%28-2%2Bi%2A2%29%5E2 Replace sqrt%28-1%29 with "i". Take the square root of 4 to get 2.


%28-2%2B2i%29%5E2 Rearrange the terms.


%28-2%29%28-2%29%2B%28-2%29%282i%29%2B%282i%29%28-2%29%2B%282i%29%282i%29 FOIL.


4-4i-4i%2B4i%5E2 Multiply.


4-4i-4i%2B4%28-1%29 Replace i%5E2 with -1. Note: i%5E2=-1.


4-4i-4i-4 Multiply.


-8i Combine like terms.


So %28-2%2Bsqrt%28-4%29%29%5E2=-8i.


Radicals/202863: This question is from textbook college algebra
How do you solve: +5+radical+-16+%2B+3+radical+-81+
1 solutions

Answer 153028 by jim_thompson5910(28595) About Me  on 2009-07-12 20:07:03 (Show Source):
You can put this solution on YOUR website!
5%2Asqrt%28-16%29%2B3%2Asqrt%28-81%29 Start with the given expression.


5%2Asqrt%28-1%2A16%29%2B3%2Asqrt%28-1%2A81%29 Factor


5%2Asqrt%28-1%29%2Asqrt%2816%29%2B3%2Asqrt%28-1%29%2Asqrt%2881%29 Break up the roots


5%2Ai%2Asqrt%2816%29%2B3%2Ai%2Asqrt%2881%29 Replace sqrt%28-1%29 with "i"


5%2Ai%2A4%2B3%2Ai%2A9 Take the square root of 16 to get 4. Take the square root of 81 to get 9.


5%2A4%2Ai%2B3%2A9%2Ai Rearrange the terms.


20%2Ai%2B27%2Ai Multiply


47%2Ai Combine like terms.


So 5%2Asqrt%28-16%29%2B3%2Asqrt%28-81%29=47%2Ai


Linear_Algebra/202859: i was wondering how would you do this problem and find its products :
(x+3)^3
and thank you in advance for helping me
1 solutions

Answer 153015 by jim_thompson5910(28595) About Me  on 2009-07-12 18:52:45 (Show Source):
You can put this solution on YOUR website!
Method # 1: The somewhat long way


%28x%2B3%29%5E3 Start with the given expression.


%28x%2B3%29%28x%2B3%29%5E2 Factor


%28x%2B3%29%28x%5E2%2B6x%2B9%29 FOIL


x%28x%5E2%2B6x%2B9%29%2B3%28x%5E2%2B6x%2B9%29 Expand


x%5E3%2B6x%5E2%2B9x%2B3x%5E2%2B18x%2B27 Distribute


x%5E3%2B9x%5E2%2B27x%2B27 Combine like terms.



So %28x%2B3%29%5E3 expands and simplifies to x%5E3%2B9x%5E2%2B27x%2B27.


In other words, %28x%2B3%29%5E3=x%5E3%2B9x%5E2%2B27x%2B27





If you didn't like method # 1, then...


Method # 2: The shorter way (if you're familiar with this method)



%28x%2B3%29%5E3 Start with the given expression

To expand this, we're going to use binomial expansion. So let's look at Pascal's triangle:
1   

1   1   

1   2   1   

1   3   3   1   




Looking at the row that starts with 1,3, etc, we can see that this row has the numbers:

1, 3, 3, and 1

These numbers will be the coefficients of our expansion. So to expand %28x%2B3%29%5E3, simply follow this procedure:
Write the first coefficient. Multiply that coefficient with the first binomial term x and then the second binomial term 3. Repeat this until all of the coefficients have been written.

Once that has been done, add up the terms like this:


Notice how the coefficients are in front of each term.



However, we're not done yet.


1%28x%29%5E3%283%29%5E0%2B%28x%29%283%29%2B3%28x%29%283%29%2B1%28x%29%283%29 Looking at the first term 1%28x%29%283%29, raise x to the 3rd power and raise 3 to the 0th power.

1%28x%29%5E3%283%29%5E0%2B%28x%29%5E2%283%29%5E1%2B3%28x%29%283%29%2B1%28x%29%283%29 Looking at the second term 3%28x%29%283%29 raise x to the 2nd power and raise 3 to the 1st power.

Continue this until you reach the final term.


Notice how the exponents of x are stepping down and the exponents of 3 are stepping up.


So the fully expanded expression should now look like this:





1%28x%5E3%29%281%29%2B3%28x%5E2%29%283%29%2B3%28x%5E1%29%289%29%2B1%28x%5E0%29%2827%29 Distribute the exponents


1%28x%5E3%29%2B3%283x%5E2%29%2B3%289x%29%2B1%2827%29 Multiply


x%5E3%2B9x%5E2%2B27x%2B27 Multiply the terms with their coefficients


So %28x%2B3%29%5E3 expands and simplifies to x%5E3%2B9x%5E2%2B27x%2B27.


In other words, %28x%2B3%29%5E3=x%5E3%2B9x%5E2%2B27x%2B27 (which is what we got before)


Exponents/202846: Solve. e^(4x^2+12x+9)= 1

1 solutions

Answer 153009 by jim_thompson5910(28595) About Me  on 2009-07-12 18:14:43 (Show Source):
You can put this solution on YOUR website!
e%5E%284x%5E2%2B12x%2B9%29=1 Start with the given equation.


ln%28e%5E%284x%5E2%2B12x%2B9%29%29=ln%281%29 Take the natural log of both sides


4x%5E2%2B12x%2B9=ln%281%29 Evaluate the natural log of e%5E%284x%5E2%2B12x%2B9%29 to get 4x%5E2%2B12x%2B9


4x%5E2%2B12x%2B9=0 Evaluate the natural log of 1 to get 0


Notice that the quadratic 4x%5E2%2B12x%2B9 is in the form of Ax%5E2%2BBx%2BC where A=4, B=12, and C=9


Let's use the quadratic formula to solve for "x":


x+=+%28-B+%2B-+sqrt%28+B%5E2-4AC+%29%29%2F%282A%29 Start with the quadratic formula


x+=+%28-%2812%29+%2B-+sqrt%28+%2812%29%5E2-4%284%29%289%29+%29%29%2F%282%284%29%29 Plug in A=4, B=12, and C=9


x+=+%28-12+%2B-+sqrt%28+144-4%284%29%289%29+%29%29%2F%282%284%29%29 Square 12 to get 144.


x+=+%28-12+%2B-+sqrt%28+144-144+%29%29%2F%282%284%29%29 Multiply 4%284%29%289%29 to get 144


x+=+%28-12+%2B-+sqrt%28+0+%29%29%2F%282%284%29%29 Subtract 144 from 144 to get 0


x+=+%28-12+%2B-+sqrt%28+0+%29%29%2F%288%29 Multiply 2 and 4 to get 8.


x+=+%28-12+%2B-+0%29%2F%288%29 Take the square root of 0 to get 0.


x+=+%28-12+%2B+0%29%2F%288%29 or x+=+%28-12+-+0%29%2F%288%29 Break up the expression.


x+=+%28-12%29%2F%288%29 or x+=++%28-12%29%2F%288%29 Combine like terms.


x+=+-3%2F2 or x+=+-3%2F2 Simplify.


So the only solution is x+=+-3%2F2


logarithm/202843: Given Log(a)=0.0441 and log(b)=0.7964; find Log[sqrt a/b] (find log square root of (a) over (b).
1 solutions

Answer 153007 by jim_thompson5910(28595) About Me  on 2009-07-12 18:00:00 (Show Source):
You can put this solution on YOUR website!
log%28%28sqrt%28a%29%2Fb%29%29 Start with the given expression.


log%28%28sqrt%28a%29%29%29-log%28%28b%29%29 Break up the log using the identity log%28%28A%2FB%29%29=log%28%28A%29%29-log%28%28B%29%29%29


log%28%28a%5E%281%2F2%29%29%29-log%28%28b%29%29 Convert to exponential notation.


%281%2F2%29log%28%28a%29%29-log%28%28b%29%29 Rewrite the first log using the identity log%28%28x%5Ey%29%29=y%2Alog%28%28x%29%29


%281%2F2%29%280.0441%29-0.7964 Plug in log%28%28a%29%29=0.0441 and log%28%28b%29%29=0.7964


0.02205-0.7964 Multiply


-0.77435 Combine like terms.


So log%28%28sqrt%28a%29%2Fb%29%29=-0.77435 when log%28%28a%29%29=0.0441 and log%28%28b%29%29=0.7964


Exponents/202841: Solve 3^2x+1=1/27
1 solutions

Answer 153006 by jim_thompson5910(28595) About Me  on 2009-07-12 17:52:17 (Show Source):
You can put this solution on YOUR website!
3%5E%282x%2B1%29=1%2F27 Start with the given equation.


3%5E%282x%2B1%29=1%2F%283%5E3%29 Rewrite 27 as 3%5E3


3%5E%282x%2B1%29=3%5E%28-3%29 Rewrite 1%2F3%5E3 as 3%5E%28-3%29


2x%2B1=-3 Since the bases are equal, this means that the exponents are equal.


2x=-3-1 Subtract 1 from both sides.


2x=-4 Combine like terms on the right side.


x=%28-4%29%2F%282%29 Divide both sides by 2 to isolate x.


x=-2 Reduce.


----------------------------------------------------------------------

Answer:

So the solution is x=-2


Functions/202840: Decreasing cube. Each of the three dimensions of a
cube with sides of length s centimeters is decreased by a
whole number of centimeters. The new volume in cubic
centimeters is given by
V(s)  s3  13s2  54s  72.
a) Find V(10).
b) If the new width is s  6 centimeters, then what are the
new length and height?
c) Find the volume when s  10 by multiplying the
length, width, and height.
Have tried the following: For A.) v(10)=10^3-13(10)^2+54(10)-72 For B. and C. I am completely lost at where to even begin.
1 solutions

Answer 153005 by jim_thompson5910(28595) About Me  on 2009-07-12 17:49:30 (Show Source):
You can put this solution on YOUR website!
Hi there,

Something must have not been copied correctly because there are a lot of box symbols all over the page. So I'm going to make a lot assumptions of what the problem really is.


a)


V%28s%29=s%5E3-13s%5E2%2B54s-72 Start with the given function.


V%2810%29=%2810%29%5E3-13%2810%29%5E2%2B54%2810%29-72 Plug in s=10 (ie replace each "s" with 10).


V%2810%29=1000-13%2810%29%5E2%2B54%2810%29-72 Cube 10 to get 1000.


V%2810%29=1000-13%28100%29%2B54%2810%29-72 Square 10 to get 100.


V%2810%29=1000-1300%2B54%2810%29-72 Multiply -13 and 100 to get -1300.


V%2810%29=1000-1300%2B540-72 Multiply 54 and 10 to get 540.


V%2810%29=168 Combine like terms.





b)


V=LWH Start with the volume equation.


s%5E3-13s%5E2%2B54s-72=L%28s-6%29H Plug in the given expressions


%28s%5E3-13s%5E2%2B54s-72%29%2F%28s-6%29=LH Divide both sides by s-6.


%28%28s-6%29%28s%5E2-7s%2B12%29%29%2F%28s-6%29=LH Factor the numerator


%28cross%28%28s-6%29%29%28s%5E2-7s%2B12%29%29%2Fcross%28%28s-6%29%29=LH Cancel out the common terms.


s%5E2-7s%2B12=LH Simplify


LH=s%5E2-7s%2B12 Rearrange the equation


LH=%28s-3%29%28s-4%29 Factor


So the new length and height are s-3 and s-4





c)

I'll let you attempt this one on your own. Repost if you still need help.


Note: the answer is going to be the same as the answer in part a) (so you'll have something to check)



Graphs/202837: how to compute the slope of the line segment determined by the pair of points(8,3) and (-6,9)
1 solutions

Answer 153004 by jim_thompson5910(28595) About Me  on 2009-07-12 17:38:27 (Show Source):
You can put this solution on YOUR website!

Note: is the first point . So this means that x%5B1%5D=8 and y%5B1%5D=3.
Also, is the second point . So this means that x%5B2%5D=-6 and y%5B2%5D=9.


m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29 Start with the slope formula.


m=%289-3%29%2F%28-6-8%29 Plug in y%5B2%5D=9, y%5B1%5D=3, x%5B2%5D=-6, and x%5B1%5D=8


m=%286%29%2F%28-6-8%29 Subtract 3 from 9 to get 6


m=%286%29%2F%28-14%29 Subtract 8 from -6 to get -14


m=-3%2F7 Reduce


So the slope of the line that goes through the points and is m=-3%2F7