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Quadratic_Equations/128744: (x+7)^2=81
1 solutions

Answer 94182 by jim_thompson5910(28595) About Me  on 2008-02-24 12:47:38 (Show Source):
You can put this solution on YOUR website!

Start with the given equation



Take the square root of both sides




Simplify the square root (note: If you need help with simplifying the square root, check out this solver)



Subtract 7 from both sides to isolate x.


Break down the expression into two parts:




   or  

 


Now combine like terms for each expression:

   or      



-----------------------------------
Answer:
So our solution is

  or   

 


Notice when we graph the equations y=%28x%2B7%29%5E2 and y=81 we get:

graph of y=%28x%2B7%29%5E2 (red) and y=81 (green)



Here we can see that the two equations intersect at x values of x=2 and x=-16, so this verifies our answer.


Systems-of-equations/128655: If f(x)=2x^2 -7x+3 find
Part A f(2)

Part B f(-3)
I have tried to solve this by plugging the 2 in for x and for part A came up with -3 and for part B came up with 42. am I doing this correctly
1 solutions

Answer 94125 by jim_thompson5910(28595) About Me  on 2008-02-23 22:10:30 (Show Source):
You can put this solution on YOUR website!
a)

Let's find f(2)

f%28x%29=2x%5E2-7x%2B3 Start with the given function


f%282%29=2%282%29%5E2-7%282%29%2B3 Plug in x=2


f%282%29=2%2A4-7%2A2%2B3 Raise 2 to the 2nd power to get 4


f%282%29=8-7%2A2%2B3 Multiply 2 and 4 to get 8


f%282%29=8-14%2B3 Multiply 7 and 2 to get 14


f%282%29=-6%2B3 Subtract 14 from 8 to get -6


f%282%29=-3 Add -6 and 3 to get -3


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

b)

Let's find f(-3)

f%28x%29=2x%5E2-7x%2B3 Start with the given function


f%28-3%29=2%28-3%29%5E2-7%28-3%29%2B3 Plug in x=-3


f%28-3%29=2%2A9-7%2A-3%2B3 Raise -3 to the 2nd power to get 9


f%28-3%29=18-7%2A-3%2B3 Multiply 2 and 9 to get 18


f%28-3%29=18--21%2B3 Multiply 7 and -3 to get -21


f%28-3%29=39%2B3 Subtract -21 from 18 to get 39


f%28-3%29=42 Add 39 and 3 to get 42




So you are correct.


Systems-of-equations/128657: ok this one I really do not understand becuase they do not give me a value for x or anything.
Part A) Calculate the value of the discriminant of x^2+x+3=0
Part B) by examining teh sign of the discriminant in part a, how many x-intercepts would the graph of y = x^2+x+3 have? Why?
I know that to get the discrimant the equation is b^2 - 4ac, and that if the discriminant is positive the the solutions will be real numbers, and if it is a negative you will have two complex solutions. but how do I solve this if I do not know what the value of b is or the value of A and C
1 solutions

Answer 94123 by jim_thompson5910(28595) About Me  on 2008-02-23 22:06:57 (Show Source):
You can put this solution on YOUR website!
From the quadratic formula
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+

the discriminant consists of all of the terms in the square root. So the discriminant is

D=b%5E2-4ac

the discriminant tells us how many solutions (and what type of solutions) we can expect for any quadratic.


Now let's find the discriminant for y=x%5E2%2Bx%2B3 (notice how a=1, b=1 and c=3):

D=b%5E2-4ac Start with the given equation

D=%281%29%5E2-4%2A1%2A3 Plug in a=1, b=1, c=3

D=1-4%2A1%2A3 Square 1 to get 1

D=1-12 Multiply -4*1*3 to get -12

D=-11 Combine 1 and -12 to get -11


Since the discriminant equals -11 (which is less than zero) , this means there are two complex solutions.


Notice if we graph y=x%5E2%2Bx%2B3, we get

+graph%28+500%2C+500%2C+-10%2C+10%2C+-10%2C+10%2C+x%5E2%2Bx%2B3%29+

and we can see that there are two complex solutions. So this visually verifies our answer.


absolute-value/128605: find the y-intercept
-x+3y=24
1 solutions

Answer 94093 by jim_thompson5910(28595) About Me  on 2008-02-23 16:35:31 (Show Source):
You can put this solution on YOUR website!
-x%2B3y=24 Start with the given equation

To find the y-intercept, let x=0 and solve for y:
0%2B3y=24 Plug in x=0

-3y=24 Simplify

x=24%2F3 Divide both sides by 3 to isolate y


y=8 Reduce



So the y-intercept is (note: the y-intercept will always have a x-coordinate equal to zero)


Functions/128612: Make a table of at least 7 ordered pairs that satisfy the equation y=x%5E2-3. Then use your table to graph the function.
1 solutions

Answer 94091 by jim_thompson5910(28595) About Me  on 2008-02-23 16:22:43 (Show Source):
You can put this solution on YOUR website!
In order to generate ordered pairs, we need to plot evaluate some x values to get some y values to get the points.


So let's find the first point:



f%28x%29=1x%5E2-3 Start with the given function


f%28-5%29=1%28-5%29%5E2-3 Plug in x=-5


f%28-5%29=1%2A25-3 Raise -5 to the 2nd power to get 25


f%28-5%29=25-3 Multiply 1 and 25 to get 25


f%28-5%29=22 Subtract 3 from 25 to get 22


So when x=-5, we have y=22


So our 1st point is (-5,22)


-------------- Let's find another point --------------


f%28x%29=1x%5E2-3 Start with the given function


f%28-4%29=1%28-4%29%5E2-3 Plug in x=-4


f%28-4%29=1%2A16-3 Raise -4 to the 2nd power to get 16


f%28-4%29=16-3 Multiply 1 and 16 to get 16


f%28-4%29=13 Subtract 3 from 16 to get 13


So when x=-4, we have y=13


So our 2nd point is (-4,13)


-------------- Let's find another point --------------


f%28x%29=1x%5E2-3 Start with the given function


f%28-3%29=1%28-3%29%5E2-3 Plug in x=-3


f%28-3%29=1%2A9-3 Raise -3 to the 2nd power to get 9


f%28-3%29=9-3 Multiply 1 and 9 to get 9


f%28-3%29=6 Subtract 3 from 9 to get 6


So when x=-3, we have y=6


So our 3rd point is (-3,6)


-------------- Let's find another point --------------


f%28x%29=1x%5E2-3 Start with the given function


f%28-2%29=1%28-2%29%5E2-3 Plug in x=-2


f%28-2%29=1%2A4-3 Raise -2 to the 2nd power to get 4


f%28-2%29=4-3 Multiply 1 and 4 to get 4


f%28-2%29=1 Subtract 3 from 4 to get 1


So when x=-2, we have y=1


So our 4th point is (-2,1)


-------------- Let's find another point --------------


f%28x%29=1x%5E2-3 Start with the given function


f%28-1%29=1%28-1%29%5E2-3 Plug in x=-1


f%28-1%29=1%2A1-3 Raise -1 to the 2nd power to get 1


f%28-1%29=1-3 Multiply 1 and 1 to get 1


f%28-1%29=-2 Subtract 3 from 1 to get -2


So when x=-1, we have y=-2


So our 5th point is (-1,-2)


-------------- Let's find another point --------------


f%28x%29=1x%5E2-3 Start with the given function


f%280%29=1%280%29%5E2-3 Plug in x=0


f%280%29=1%2A0-3 Raise 0 to the 2nd power to get 0


f%280%29=0-3 Multiply 1 and 0 to get 0


f%280%29=-3 Subtract 3 from 0 to get -3


So when x=0, we have y=-3


So our 6th point is (0,-3)


-------------- Let's find another point --------------


f%28x%29=1x%5E2-3 Start with the given function


f%281%29=1%281%29%5E2-3 Plug in x=1


f%281%29=1%2A1-3 Raise 1 to the 2nd power to get 1


f%281%29=1-3 Multiply 1 and 1 to get 1


f%281%29=-2 Subtract 3 from 1 to get -2


So when x=1, we have y=-2


So our 7th point is (1,-2)


-------------- Let's find another point --------------


f%28x%29=1x%5E2-3 Start with the given function


f%282%29=1%282%29%5E2-3 Plug in x=2


f%282%29=1%2A4-3 Raise 2 to the 2nd power to get 4


f%282%29=4-3 Multiply 1 and 4 to get 4


f%282%29=1 Subtract 3 from 4 to get 1


So when x=2, we have y=1


So our 8th point is (2,1)


-------------- Let's find another point --------------


f%28x%29=1x%5E2-3 Start with the given function


f%283%29=1%283%29%5E2-3 Plug in x=3


f%283%29=1%2A9-3 Raise 3 to the 2nd power to get 9


f%283%29=9-3 Multiply 1 and 9 to get 9


f%283%29=6 Subtract 3 from 9 to get 6


So when x=3, we have y=6


So our 9th point is (3,6)


-------------- Let's find another point --------------


f%28x%29=1x%5E2-3 Start with the given function


f%284%29=1%284%29%5E2-3 Plug in x=4


f%284%29=1%2A16-3 Raise 4 to the 2nd power to get 16


f%284%29=16-3 Multiply 1 and 16 to get 16


f%284%29=13 Subtract 3 from 16 to get 13


So when x=4, we have y=13


So our 10th point is (4,13)


-------------- Let's find another point --------------


f%28x%29=1x%5E2-3 Start with the given function


f%285%29=1%285%29%5E2-3 Plug in x=5


f%285%29=1%2A25-3 Raise 5 to the 2nd power to get 25


f%285%29=25-3 Multiply 1 and 25 to get 25


f%285%29=22 Subtract 3 from 25 to get 22


So when x=5, we have y=22


So our 11th point is (5,22)


Now lets make a table of the values we have calculated
xy
-522
-413
-36
-21
-1-2
0-3
1-2
21
36
413
522

Now plot the points. Note: you need to use Firefox to see the next two graphs.



Now connect the points to graph y=1x%5E2-3 (note: the more points you plot, the easier it is to draw the graph)


Functions/128610: Let f%28x%29=3x,g%28x%29=3x-3 and h%28x%29=%28f%2Ag%29%28x%29%2B%28f%2Fg%29%28x%29

Complete the table
xf(x)g(x)h(x)
-1-3  
1%2F3 -2 
 12 109%261%2F3





1 solutions

Answer 94090 by jim_thompson5910(28595) About Me  on 2008-02-23 16:11:10 (Show Source):
You can put this solution on YOUR website!
xf(x)g(x)h(x)
-1-3  
1%2F3 -2 
 12 109%26amp%3B1%2F3



Let's find the first entry of g(x)

g%28x%29=3x-3 Start with the second function


g%28-1%29=3%28-1%29-3 Plug in x=1%2F3


g%28-1%29=-3-3 Multiply


g%28-1%29=-6 Subtract


So our table becomes

xf(x)g(x)h(x)
-1-3-6 
1%2F3 -2 
 12 109%26amp%3B1%2F3


Let's find the second entry of f(x)


f%28x%29=3x Start with the first function


f%281%2F3%29=3%281%2F3%29 Plug in x=1%2F3


f%281%2F3%29=3%2F3 Multiply


f%281%2F3%29=1 Reduce



Now our table updates to

xf(x)g(x)h(x)
-1-3-6 
1%2F31-2 
 12 109%26amp%3B1%2F3



Let's find the third entry of x


f%28x%29=3x Start with the first function


12=3x Plug in f%28x%29=12


4=x Divide both sides by 3 to isolate x


x=4


Now plug this value into the last row of the x column

xf(x)g(x)h(x)
-1-3-6 
1%2F31-2 
412 109%26amp%3B1%2F3



Let's find the third entry of g(x)


g%28x%29=3x-3 Start with the second function


g%284%29=3%284%29-3 Plug in x=4


g%284%29=12-3 Multiply


g%284%29=9 Subtract


Now plug this into the last entry of the g(x) column

xf(x)g(x)h(x)
-1-3-6 
1%2F31-2 
4129109%261%2F3




Now let's find the first entry of h(x)

h%28x%29=%28f%2Ag%29%28x%29%2B%28f%2Fg%29%28x%29 Start with the given function


h%28x%29=f%28x%29%2Ag%28x%29%2Bf%28x%29%2Fg%28x%29 Break up the function


h%28-1%29=f%28-1%29%2Ag%28-1%29%2Bf%28-1%29%2Fg%28-1%29 Plug in x=-1


h%28-1%29=-3%2A%28-6%29%2B%28-3%29%2F%28-6%29 Plug in f%28-1%29=-3, g%28-1%29=-6 (these values are from the table)


h%28-1%29=18%2B1%2F2 Multiply


h%28-1%29=37%2F2 Add


xf(x)g(x)h(x)
-1-3-637%2F2
1%2F31-2 
4129109%261%2F3






Now let's find the first entry of h(x)

h%28x%29=%28f%2Ag%29%28x%29%2B%28f%2Fg%29%28x%29 Start with the given function


h%28x%29=f%28x%29%2Ag%28x%29%2Bf%28x%29%2Fg%28x%29 Break up the function


h%281%2F3%29=f%281%2F3%29%2Ag%281%2F3%29%2Bf%281%2F3%29%2Fg%281%2F3%29 Plug in x=1%2F3



h%281%2F3%29=1%2A%28-2%29%2B%281%29%2F%28-2%29 Plug in f%281%2F3%29=1, g%281%2F3%29=-2 (these values are from the table)



h%281%2F3%29=-2-1%2F2 Multiply and reduce


h%281%2F3%29=-5%2F2 Combine the fractions



xf(x)g(x)h(x)
-1-3-637%2F2
1%2F31-2-5%2F2
4129109%261%2F3



Linear-equations/128597: find the slope of the line containing the pair of points (9,0) and (10,6). Simplify your answer, type an integer or a fraction.
1 solutions

Answer 94089 by jim_thompson5910(28595) About Me  on 2008-02-23 15:41:51 (Show Source):
You can put this solution on YOUR website!

Let's denote the first point (9,0) as . In other words, and

Now let's denote the second point (10,6) as . In other words, and



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



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

m=%286-0%29%2F%2810-9%29 Plug in y%5B2%5D=6,y%5B1%5D=0,x%5B2%5D=10,x%5B1%5D=9


m=6%2F1 Subtract the terms in the numerator 6-0 to get 6. Subtract the terms in the denominator 10-9 to get 1

m=6 Reduce


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

So the slope of the line through the points (9,0) and (10,6) is m=6


Inequalities/128595: Solve and graph the solution set of 4x > 7x + 20. If a unique solution does
-
not exist, state whether the system is dependent or inconsistent.
I can't fiqure this one out
1 solutions

Answer 94086 by jim_thompson5910(28595) About Me  on 2008-02-23 14:26:42 (Show Source):
You can put this solution on YOUR website!
4x%3E7x%2B20 Start with the given inequality



4x-7x%3E20 Subtract 7x from both sides


-3x%3E20 Combine like terms on the left side


x%3C%2820%29%2F%28-3%29 Divide both sides by -3 to isolate x (note: Remember, dividing both sides by a negative number flips the inequality sign)



x%3C-20%2F3 Reduce

--------------------------------------------------------------
Answer:
So our answer is x%3C-20%2F3 (which is approximately x%3C-6.667 in decimal form)




Now let's graph the solution set


Start with the given inequality:

x%3C-6.667

Set up a number line:
number_line%28500%2C-16.667%2C3.333%29

Now plot the point x=-6.667 on the number line


number_line%28500%2C-16.667%2C3.333%2C+-6.667%29


Now pick any test point you want, I'm going to choose x=0, and test the inequality x%3C-6.667


0%3C-6.667 Plug in x=0


Since this inequality is not true, we simply shade the entire portion that does not contain the point x=0 using the point x=-6.667 as the boundary. This means we shade everything to the left of the point x=-6.667 like this:
Graph of x%3C-6.667 with the shaded region in blue

note: at the point x=-6.667, there is an open circle. This means the point x=-6.667 is excluded from the solution set.


Expressions-with-variables/128583: Simplify


3(2r - 5) + 8(r + 2)

Simplify to make easier please thanks!
1 solutions

Answer 94085 by jim_thompson5910(28595) About Me  on 2008-02-23 14:20:47 (Show Source):
You can put this solution on YOUR website!
3%282r+-+5%29+%2B+8%28r+%2B+2%29+ Start with the given expression


6r+-+15+%2B+8r+%2B+16+ Distribute



%286r%2B8r%29%2B%28-15%2B16%29 Group like terms


14r%2B1 Combine like terms


So 3%282r+-+5%29+%2B+8%28r+%2B+2%29 simplifies to 14r%2B1


In other words, 3%282r+-+5%29+%2B+8%28r+%2B+2%29+=14r%2B1


Inequalities/128582: Solve the inequality.
y - 6 < 9
Any help please! Thanks
1 solutions

Answer 94084 by jim_thompson5910(28595) About Me  on 2008-02-23 14:17:42 (Show Source):
You can put this solution on YOUR website!

y-6%3C9 Start with the given inequality



y%3C9%2B6Add 6 to both sides


y%3C15 Combine like terms on the right side

--------------------------------------------------------------
Answer:
So our answer is y%3C15



Equations/128592: Solve:
9x – 10 = 3x - 1

1 solutions

Answer 94083 by jim_thompson5910(28595) About Me  on 2008-02-23 14:16:57 (Show Source):
You can put this solution on YOUR website!

9x-10=3x-1 Start with the given equation



9x=3x-1%2B10Add 10 to both sides


9x-3x=-1%2B10 Subtract 3x from both sides


6x=-1%2B10 Combine like terms on the left side


6x=9 Combine like terms on the right side


x=%289%29%2F%286%29 Divide both sides by 6 to isolate x



x=3%2F2 Reduce

--------------------------------------------------------------
Answer:
So our answer is x=3%2F2 (which is approximately x=1.5 in decimal form)


Functions/128591: Graph the inverse function

1 solutions

Answer 94082 by jim_thompson5910(28595) About Me  on 2008-02-23 14:15:06 (Show Source):
You can put this solution on YOUR website!

Start with the original graph





In order to graph the inverse function, simply reflect the original graph over the line y=x (the dashed line)


(note: for some reason, the following image does not display correctly in Internet Explorer. So I recommend the use of Firefox to see this image.)



Graph of the original function (red line) and the inverse function (blue line)


Functions/128590: The given function is f%28x%29=20000-15x


Find f%5E%28-1%29%2850%29

1 solutions

Answer 94079 by jim_thompson5910(28595) About Me  on 2008-02-23 13:55:24 (Show Source):
You can put this solution on YOUR website!
f%28x%29=20000-15x Start with the given function


To find f%5E%28-1%29%28x%29, simply swap x and f(x) to get

x=20000-15f%28x%29


15f%28x%29%2Bx=20000 Add 15f(x) to both sides


15f%28x%29=20000-x Subtract x from both sides


f%28x%29=%2820000-x%29%2F15 Divide both sides by 15 to isolate f(x)


So the inverse function is f%5E%28-1%29%28x%29=%2820000-x%29%2F15


f%5E%28-1%29%2850%29=%2820000-50%29%2F15 Now plug in x=50


f%5E%28-1%29%2850%29=%2819950%29%2F15 Subtract


f%5E%28-1%29%2850%29=1330 Divide


Functions/128579: Find the domain and range of the following:

1 solutions

Answer 94078 by jim_thompson5910(28595) About Me  on 2008-02-23 13:06:45 (Show Source):
You can put this solution on YOUR website!


Looking at the graph, notice how the graph extends to infinity in both directions in the x direction. So this shows us that there are no restrictions on the domain.



Since we don't have any restrictions on the domain, this shows us that the domain is all real numbers. In other words, we can plug in any in for x




So the domain of the function in set-builder notation is:





In plain English, this reads: x is the set of all real numbers (In other words, x can be any number)


Also, in interval notation, the domain is:




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




From the graph, we can see that the lowest point is (0,-3). So the smallest that y can be is -3



So the range of the function in set-builder notation is:





In plain English, this reads: y is the set of all real numbers that are greater than or equal to -3

Also, in interval notation, the range is:

[-3,)


Functions/128578: Find the domain and range of the following:

1 solutions

Answer 94077 by jim_thompson5910(28595) About Me  on 2008-02-23 12:59:56 (Show Source):
You can put this solution on YOUR website!


Looking at the graph, notice how the line extends to infinity in all four directions. So this shows us that there are no restrictions on the domain.



Since we don't have any restrictions on the domain, this shows us that the domain is all real numbers. In other words, we can plug in any in for x




So the domain of the function in set-builder notation is:





In plain English, this reads: x is the set of all real numbers (In other words, x can be any number)


Also, in interval notation, the domain is:




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


Also, since there are no restrictions on the range, this means that the range is all real numbers.




So the range of the function in set-builder notation is:





In plain English reads: y is the set of all real numbers (In other words, y can be any number)


Also, in interval notation, the range is:




Functions/128577: Find the domain and range of the following:

1 solutions

Answer 94076 by jim_thompson5910(28595) About Me  on 2008-02-23 12:53:07 (Show Source):
You can put this solution on YOUR website!


Looking at the graph, notice how both the x-values and y-values are restricted. In other words, we cannot plug in x=10 (as it does not fall on the curve). So we can only plug in x-values from -4 to 4. So the domain is -4%3C=x%3C=4


which in set-builder notation is




In plain English, this reads: x is the set of all real numbers that are in between -4 and 4




Also, in interval notation, the domain is:

[-4,4]



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

This also applies to the range. The range is also -4%3C=y%3C=4.



Which in set-builder notation is




In plain English, this reads: y is the set of all real numbers that are in between -4 and 4




Also, in interval notation, the range is:

[-4,4]




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

Summary:

So the domain and range are both [-4,4]


Functions/128576: Find the domain and range of the following:

b) y=%28x-2%29%5E2

1 solutions

Answer 94075 by jim_thompson5910(28595) About Me  on 2008-02-23 12:44:32 (Show Source):
You can put this solution on YOUR website!


Looking at y=%28x-2%29%5E2, we can see that there are no square roots, logs, and other functions where there are restrictions on the domain.

Also, we can see that the function does not have a division by x (or any combination of variables and constants).
So we don't have to worry about division by zero.


Since we don't have any restrictions on the domain, this shows us that the domain is all real numbers. In other words, we can plug in any in for x




So the domain of the function in set-builder notation is:





In plain English reads: x is the set of all real numbers (In other words, x can be any number)


Also, in interval notation, the domain is:









Now to find the range, simply graph the function to get




graph%28500%2C500%2C-10%2C10%2C-10%2C10%2C%28x-2%29%5E2%29



From the graph, we can see that the lowest point is (2,0). So the smallest that y can be is 0



So the range of the function in set-builder notation is:





In plain English reads: y is the set of all real numbers that are greater than or equal to 0

Also, in interval notation, the range is:

[0,)


Functions/128575: Find the domain and range of the following:

a) y=x%5E2-2

1 solutions

Answer 94074 by jim_thompson5910(28595) About Me  on 2008-02-23 12:40:08 (Show Source):
You can put this solution on YOUR website!

Looking at y=x%5E2-2, we can see that there are no square roots, logs, and other functions where there are restrictions on the domain.

Also, we can see that the function does not have a division by x (or any combination of variables and constants).
So we don't have to worry about division by zero.


Since we don't have any restrictions on the domain, this shows us that the domain is all real numbers. In other words, we can plug in any in for x




So the domain of the function in set-builder notation is:





In plain English reads: x is the set of all real numbers (In other words, x can be any number)


Also, in interval notation, the domain is:









Now to find the range, simply graph the function to get




graph%28500%2C500%2C-10%2C10%2C-10%2C10%2Cx%5E2-2%29





From the graph, we can see that the lowest point is (0,-2). So the smallest that y can be is -2



So the range of the function in set-builder notation is:





In plain English reads: y is the set of all real numbers that are greater than or equal to -2

Also, in interval notation, the range is:

[-2,)


Equations/128569: Hi Can I have some help with the following function?
A function f is given.
f(x) = √6x - 8

(a) Find f -1.
1 solutions

Answer 94073 by jim_thompson5910(28595) About Me  on 2008-02-23 12:37:04 (Show Source):
You can put this solution on YOUR website!
Is this what the function looks like: f%28x%29=sqrt%286x-8%29 ?


f%28x%29=sqrt%286x-8%29 Start with the given equation


f%28-1%29=sqrt%286%28-1%29-8%29 Plug in x=-1


f%28-1%29=sqrt%28-6-8%29 Multiply


f%28-1%29=sqrt%28-14%29 Subtract


If you have not learned about imaginary numbers, then this is where you would stop. If you have, then...


f%28-1%29=i%2Asqrt%2814%29 Simplify the square root





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

OR


Is this what the function looks like: f%28x%29=sqrt%286x%29-8 ?


f%28x%29=sqrt%286x%29-8 Start with the given equation


f%28-1%29=sqrt%286%28-1%29%29-8 Plug in x=-1


f%28-1%29=sqrt%28-6%29-8 Multiply


f%28-1%29=i%2Asqrt%286%29-8 Simplify the square root


f%28-1%29=-8%2Bi%2Asqrt%286%29 Rearrange the terms


Functions/128568: Find the domain and range of the following:

c) y=3x%5E2


d) y=x%5E2%2B4x%2B4
1 solutions

Answer 94072 by jim_thompson5910(28595) About Me  on 2008-02-23 12:31:03 (Show Source):
You can put this solution on YOUR website!
c)

Looking at y=3x%5E2, we can see that there are no square roots, logs, and other functions where there are restrictions on the domain.

Also, we can see that the function does not have a division by x (or any combination of variables and constants).
So we don't have to worry about division by zero.


Since we don't have any restrictions on the domain, this shows us that the domain is all real numbers. In other words, we can plug in any in for x




So the domain of the function in set-builder notation is:





In plain English reads: x is the set of all real numbers (In other words, x can be any number)


Also, in interval notation, the domain is:









Now to find the range, simply graph the function to get




graph%28500%2C500%2C-10%2C10%2C-10%2C10%2C3x%5E2%29


From the graph, we can see that the lowest point is (0,0). So the smallest that y can be is 0




So the range of the function in set-builder notation is:





In plain English reads: y is the set of all real numbers that are greater than or equal to 0

Also, in interval notation, the range is:

[0,)








d)





Looking at y=x%5E2%2B4x%2B4, we can see that there are no square roots, logs, and other functions where there are restrictions on the domain.

Also, we can see that the function does not have a division by x (or any combination of variables and constants).
So we don't have to worry about division by zero.


Since we don't have any restrictions on the domain, this shows us that the domain is all real numbers. In other words, we can plug in any in for x




So the domain of the function in set-builder notation is:





In plain English reads: x is the set of all real numbers (In other words, x can be any number)


Also, in interval notation, the domain is:









Now to find the range, simply graph the function to get




graph%28500%2C500%2C-10%2C10%2C-10%2C10%2Cx%5E2%2B4x%2B4%29






From the graph, we can see that the lowest point is (-2,0). So the smallest that y can be is 0



So the range of the function in set-builder notation is:





In plain English reads: y is the set of all real numbers that are greater than or equal to 0

Also, in interval notation, the range is:

[0,)


Functions/128565: Find the domain and range of the following:

a) y=x%5E2%2B3


b) y=x%5E2-5
1 solutions

Answer 94071 by jim_thompson5910(28595) About Me  on 2008-02-23 12:25:16 (Show Source):
You can put this solution on YOUR website!
a)

Looking at y=x%5E2%2B3, we can see that there are no square roots, logs, and other functions where there are restrictions on the domain.

Also, we can see that the function does not have a division by x (or any combination of variables and constants).
So we don't have to worry about division by zero.


Since we don't have any restrictions on the domain, this shows us that the domain is all real numbers. In other words, we can plug in any in for x




So the domain of the function in set-builder notation is:





In plain English reads: x is the set of all real numbers (In other words, x can be any number)


Also, in interval notation, the domain is:









Now to find the range, simply graph the function to get




graph%28500%2C500%2C-10%2C10%2C-10%2C10%2Cx%5E2%2B3%29


From the graph, we can see that the lowest point is (0,3). So the smallest that y can be is 3




So the range of the function in set-builder notation is:





In plain English reads: y is the set of all real numbers that are greater than 3

Also, in interval notation, the range is:

[3,)








b)





Looking at y=x%5E2-5, we can see that there are no square roots, logs, and other functions where there are restrictions on the domain.

Also, we can see that the function does not have a division by x (or any combination of variables and constants).
So we don't have to worry about division by zero.


Since we don't have any restrictions on the domain, this shows us that the domain is all real numbers. In other words, we can plug in any in for x




So the domain of the function in set-builder notation is:





In plain English reads: x is the set of all real numbers (In other words, x can be any number)


Also, in interval notation, the domain is:









Now to find the range, simply graph the function to get




graph%28500%2C500%2C-10%2C10%2C-10%2C10%2Cx%5E2-5%29






From the graph, we can see that the lowest point is (0,-5). So the smallest that y can be is -5



So the range of the function in set-builder notation is:





In plain English reads: y is the set of all real numbers that are greater than -5

Also, in interval notation, the range is:

[-5,)


Equations/128537: This question is from textbook Pre-Algebra
I can't figure this out at all.
Problem #44 states: Suppose %281%2A10%5Ea%29%2B%282%2A10%5Eb%29%2B%283%2A10%5Ec%29%2B%284%2A10%5Ed%29=24130, and a,b,c and d are all positive integers. Find the value of %28a%2Bb%2Bc%2Bd%29%2F16.
I don't even know how to begin. I understood this chapter up to this question.
Thanks.
1 solutions

Answer 94070 by jim_thompson5910(28595) About Me  on 2008-02-23 12:17:23 (Show Source):
You can put this solution on YOUR website!
Remember, the number 24,130 can be broken up like this:









So this shows us that which means . Also, which means . This continues until you run out of variables.

So we have the values

a=2, b=4, c=1, and d=3



So %28a%2Bb%2Bc%2Bd%29%2F16 becomes %282%2B4%2B1%2B3%29%2F16=10%2F16=5%2F8


Polynomials-and-rational-expressions/128560: Can you please help me understand the rules and format for this type of math?

(6x^2-4x+7)+(2x^2-3x-9)=
I tried this one,but i cant figured it out?
6x-(4x-5)=13
6x+(4x+5)=13

1 solutions

Answer 94069 by jim_thompson5910(28595) About Me  on 2008-02-23 11:53:44 (Show Source):
You can put this solution on YOUR website!
%286x%5E2-4x%2B7%29%2B%282x%5E2-3x-9%29 Start with the given expression


%286x%5E2%2B2x%5E2%29%2B%28-4x-3x%29%2B%287-9%29 Group like terms


8x%5E2-7x-2 Combine like terms


Polynomials-and-rational-expressions/128558: This question is from textbook Introductory Algebra
I think I came up with the right answer, but would love for someone to double-check my work! The problem reads: Solve
3a-5/a^2+4a+3 + 2a+2/a+3 = a-3/a+1
I came up with a = -6 or -1
1 solutions

Answer 94068 by jim_thompson5910(28595) About Me  on 2008-02-23 11:51:57 (Show Source):
You can put this solution on YOUR website!

Let's verify the solution a=-6



%283a-5%29%2F%28a%5E2%2B4a%2B3%29+%2B+%282a%2B2%29%2F%28a%2B3%29=%28a-3%29%2F%28a%2B1%29 Start with the given equation


Plug in a=-6. In other words, replace each a with -6



%28-18-5%29%2F%2836-24%2B3%29+%2B+%28-12%2B2%29%2F%28-6%2B3%29=%28-6-3%29%2F%28-6%2B1%29 Square and multiply


-23%2F15+%2B+10%2F3=9%2F5 Combine like terms


9%2F5=9%2F5 Combine the fractions on the right side and reduce


Since the two sides of the equation are equal, this verifies our answer.




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




Let's verify the solution a=-1



%283a-5%29%2F%28a%5E2%2B4a%2B3%29+%2B+%282a%2B2%29%2F%28a%2B3%29=%28a-3%29%2F%28a%2B1%29 Start with the given equation


Plug in a=-1. In other words, replace each a with -1



%28-3-5%29%2F%281-4%2B3%29+%2B+%28-2%2B2%29%2F%28-1%2B3%29=%28-1-3%29%2F%28-1%2B1%29 Square and multiply


%28-8%29%2F%280%29+%2B+0%2F%282%29=%28-4%29%2F%280%29 Combine like terms



Notice how there are denominators of zero. Since division by zero is undefined, a=-1 is not a solution of the equation.




So our only solution is

a=-6


Functions/128507: Find the domain and range of the following

d)
y=7%2F%28x%2B9%29

e)
y=3%2F%28x%5E2-4%29



1 solutions

Answer 94022 by jim_thompson5910(28595) About Me  on 2008-02-22 19:29:32 (Show Source):
You can put this solution on YOUR website!
# 1

d)

y=%287%29%2F%28x%2B9%29 Start with the given function


x%2B9=0 Set the denominator equal to zero. Remember, dividing by 0 is undefined. So if we find values of x that make the denominator zero, then we must exclude them from the domain.



x=0-9Subtract 9 from both sides


x=-9 Combine like terms on the right side





Since x=-9 makes the denominator equal to zero, this means we must exclude x=-9 from our domain

So our domain is:

which in plain English reads: x is the set of all real numbers except x%3C%3E-9

So our domain looks like this in interval notation


note: remember, the parenthesis excludes -9 from the domain

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




Now to find the range, simply graph the function to get


note: ignore the vertical lines, they are not part of the graph and are asymptotes
graph%28500%2C500%2C-15%2C5%2C-10%2C10%2C%287%29%2F%28x%2B9%29%29


Looking at the graph, we can see that y can be any number except 0. So y%3C%3E0.




So our range is:

which in plain English reads: y is the set of all real numbers except y%3C%3E0

So our range looks like this in interval notation


note: remember, the parenthesis excludes 0 from the range






e)





y=%283%29%2F%28x%5E2-4%29 Start with the given function


x%5E2-4=0 Set the denominator equal to zero. Remember, dividing by 0 is undefined. So if we find values of x that make the denominator zero, then we must exclude them from the domain.




%28x-2%29%28x%2B2%29=0 Factor the left side (note: if you need help with factoring, check out this solver)




Now set each factor equal to zero:

x-2=0 or x%2B2=0

x=2 or x=-2 Now solve for x in each case


So our solutions are x=2 or x=-2



Since x=-2 and x=2 make the denominator equal to zero, this means we must exclude x=-2 and x=2 from our domain

So our domain is:

which in plain English reads: x is the set of all real numbers except x%3C%3E-2 or x%3C%3E2

So our domain looks like this in interval notation


note: remember, the parenthesis excludes -2 and 2 from the domain



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




Now to find the range, simply graph the function to get




note: ignore the vertical lines, they are not part of the graph and are asymptotes

graph%28500%2C500%2C-15%2C5%2C-10%2C10%2C%283%29%2F%28x%5E2-4%29%29


Looking at the graph, we can see that y can be any number except 0. So y%3C%3E0.




So our range is:

which in plain English reads: y is the set of all real numbers except y%3C%3E0

So our range looks like this in interval notation


note: remember, the parenthesis excludes 0 from the range


Functions/128504: Find the domain and range of the following

a)
y=3x-4

b)
y=%28x%2B9%29%2F7

c)

y=x%5E3%2B5

1 solutions

Answer 94021 by jim_thompson5910(28595) About Me  on 2008-02-22 19:11:45 (Show Source):
You can put this solution on YOUR website!
# 1

a)




Looking at y=3x-4, we can see that there are no square roots, logs, and other functions where there are restrictions on the domain.

Also, we can see that the function does not have a division by x (or any combination of variables and constants).
So we don't have to worry about division by zero.


Since we don't have any restrictions on the domain, this shows us that the domain is all real numbers. In other words, we can plug in any in for x




So the domain of the function in set-builder notation is:





In plain English reads: x is the set of all real numbers (In other words, x can be any number)


Also, in interval notation, the domain is:









Now to find the range, simply graph the function to get




graph%28500%2C500%2C-10%2C10%2C-10%2C10%2C3x-4%29




From the graph, we can see that the function's y-values extend forever in both directions. So the range is also all real numbers

So the range of the function in set-builder notation is:





In plain English reads: y is the set of all real numbers (In other words, y can be any number)


Also, in interval notation, the range is:









b)





Looking at y=%28x%2B9%29%2F7, we can see that there are no square roots, logs, and other functions where there are restrictions on the domain.

Also, we can see that the function does not have a division by x (or any combination of variables and constants).
So we don't have to worry about division by zero.


Since we don't have any restrictions on the domain, this shows us that the domain is all real numbers. In other words, we can plug in any in for x




So the domain of the function in set-builder notation is:





In plain English reads: x is the set of all real numbers (In other words, x can be any number)


Also, in interval notation, the domain is:









Now to find the range, simply graph the function to get




graph%28500%2C500%2C-20%2C20%2C-20%2C20%2C%28x%2B9%29%2F7%29





From the graph, we can see that the function's y-values extend forever in both directions. So the range is also all real numbers

So the range of the function in set-builder notation is:





In plain English reads: y is the set of all real numbers (In other words, y can be any number)


Also, in interval notation, the range is:










c)





Looking at y=x%5E3%2B5, we can see that there are no square roots, logs, and other functions where there are restrictions on the domain.

Also, we can see that the function does not have a division by x (or any combination of variables and constants).
So we don't have to worry about division by zero.


Since we don't have any restrictions on the domain, this shows us that the domain is all real numbers. In other words, we can plug in any in for x




So the domain of the function in set-builder notation is:





In plain English reads: x is the set of all real numbers (In other words, x can be any number)


Also, in interval notation, the domain is:









Now to find the range, simply graph the function to get




graph%28500%2C500%2C-10%2C10%2C-10%2C10%2Cx%5E3%2B5%29




From the graph, we can see that the function's y-values extend forever in both directions. So the range is also all real numbers





So the range of the function in set-builder notation is:





In plain English reads: y is the set of all real numbers (In other words, y can be any number)


Also, in interval notation, the range is:




Expressions-with-variables/128496: Solve by addition. If a unique solution does not exist, state whether the system is inconsistent or dependent.
4x – 3y = 22
5x + 4y = 6

1 solutions

Answer 94020 by jim_thompson5910(28595) About Me  on 2008-02-22 18:38:53 (Show Source):
You can put this solution on YOUR website!

Start with the given system of equations:

system%284x-3y=22%2C5x%2B4y=6%29



Now in order to solve this system by using elimination/addition, we need to solve (or isolate) one variable. I'm going to solve for y.





In order to solve for one variable, we must eliminate the other variable. So if we wanted to solve for y, we would have to eliminate x (or vice versa).


So lets eliminate x. In order to do that, we need to have both x coefficients that are equal in magnitude but have opposite signs (for instance 2 and -2 are equal in magnitude but have opposite signs). This way they will add to zero. By adding to zero, they can be eliminated.



So to make the x coefficients equal in magnitude but opposite in sign, we need to multiply both x coefficients by some number to get them to an common number. So if we wanted to get 4 and 5 to some equal number, we could try to get them to the LCM.



Since the LCM of 4 and 5 is 20, we need to multiply both sides of the top equation by 5 and multiply both sides of the bottom equation by -4 like this:




5%284x-3y%29=5%2822%29 Multiply the top equation (both sides) by 5
-4%285x%2B4y%29=-4%286%29 Multiply the bottom equation (both sides) by -4




Distribute and multiply

20x-15y=110
-20x-16y=-24


Now add the equations together. In order to add 2 equations, group like terms and combine them

%2820x-20x%29%2B%28-15y-16y%29=110-24

Combine like terms and simplify



cross%2820x-20x%29-31y=86 Notice how the x terms cancel out




-31y=86 Simplify




y=86%2F-31 Divide both sides by -31 to isolate y




y=-86%2F31 Reduce



Now plug this answer into the top equation 4x-3y=22 to solve for x

4x-3y=22 Start with the first equation



4x-3%28-86%2F31%29=22 Plug in y=-86%2F31




4x%2B258%2F31=22 Multiply



%2831%29%284x%2B258%2F31%29=%2831%29%2822%29 Multiply both sides by the LCM of 31. This will eliminate the fractions (note: if you need help with finding the LCM, check out this solver)



124x%2B258=682 Distribute and multiply the LCM to each side



124x=682-258Subtract 258 from both sides


124x=424 Combine like terms on the right side


x=%28424%29%2F%28124%29 Divide both sides by 124 to isolate x



x=106%2F31 Reduce




So our answer is
x=106%2F31 and y=-86%2F31



which also looks like


Linear-equations/128493: Find the slope of the line passing through the pair of points or state that the slope is undefined.
(4,2) and (7,8)
(-7,-9) and (3,-2)
(6,3) and (6,-4)
(7,-4) and (-9,-4)
1 solutions

Answer 94019 by jim_thompson5910(28595) About Me  on 2008-02-22 18:30:23 (Show Source):
You can put this solution on YOUR website!
I'll do the first two to get you started


# 1




Let's denote the first point (4,2) as . In other words, and

Now let's denote the second point (7,8) as . In other words, and



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



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

m=%288-2%29%2F%287-4%29 Plug in y%5B2%5D=8,y%5B1%5D=2,x%5B2%5D=7,x%5B1%5D=4


m=6%2F3 Subtract the terms in the numerator 8-2 to get 6. Subtract the terms in the denominator 7-4 to get 3

m=2 Reduce


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

So the slope of the line through the points (4,2) and (7,8) is m=2









# 2




Let's denote the first point (-7,-9) as . In other words, and

Now let's denote the second point (3,-2) as . In other words, and



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



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

m=%28-2--9%29%2F%283--7%29 Plug in y%5B2%5D=-2,y%5B1%5D=-9,x%5B2%5D=3,x%5B1%5D=-7


m=7%2F10 Subtract the terms in the numerator -2--9 to get 7. Subtract the terms in the denominator 3--7 to get 10

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

So the slope of the line through the points (-7,-9) and (3,-2) is m=7%2F10


Equations/128458: how to write 12x + 3y = 6 in function form and then graph.
also 4x - 2y = 16
1 solutions

Answer 94018 by jim_thompson5910(28595) About Me  on 2008-02-22 18:27:31 (Show Source):
You can put this solution on YOUR website!
# 1


12x%2B3y=6 Start with the given equation


3y=6-12x Subtract 12+x from both sides


3y=-12x%2B6 Rearrange the equation


y=%28-12x%2B6%29%2F%283%29 Divide both sides by 3


y=%28-12%2F3%29x%2B%286%29%2F%283%29 Break up the fraction


y=-4x%2B2 Reduce



So the equation is now in slope-intercept form (y=mx%2Bb) where the slope is m=-4 and the y-intercept is b=2


So to get the equation into function form, simply replace y with f(x)



So the equation changes to the function f%28x%29=-4x%2B2






Looking at y=-4x%2B2 we can see that the equation is in slope-intercept form y=mx%2Bb where the slope is m=-4 and the y-intercept is b=2


Since b=2 this tells us that the y-intercept is .Remember the y-intercept is the point where the graph intersects with the y-axis

So we have one point




Now since the slope is comprised of the "rise" over the "run" this means
slope=rise%2Frun

Also, because the slope is -4, this means:

rise%2Frun=-4%2F1


which shows us that the rise is -4 and the run is 1. This means that to go from point to point, we can go down 4 and over 1



So starting at , go down 4 units


and to the right 1 unit to get to the next point



Now draw a line through these points to graph y=-4x%2B2

So this is the graph of y=-4x%2B2 through the points and







# 2





4x-2y=16 Start with the given equation


-2y=16-4x Subtract 4+x from both sides


-2y=-4x%2B16 Rearrange the equation


y=%28-4x%2B16%29%2F%28-2%29 Divide both sides by -2


y=%28-4%2F-2%29x%2B%2816%29%2F%28-2%29 Break up the fraction


y=2x-8 Reduce



So the equation is now in slope-intercept form (y=mx%2Bb) where the slope is m=2 and the y-intercept is b=-8



So to get the equation into function form, simply replace y with f(x)



So the equation changes to the function f%28x%29=2x-8





Looking at y=2x-8 we can see that the equation is in slope-intercept form y=mx%2Bb where the slope is m=2 and the y-intercept is b=-8


Since b=-8 this tells us that the y-intercept is .Remember the y-intercept is the point where the graph intersects with the y-axis

So we have one point




Now since the slope is comprised of the "rise" over the "run" this means
slope=rise%2Frun

Also, because the slope is 2, this means:

rise%2Frun=2%2F1


which shows us that the rise is 2 and the run is 1. This means that to go from point to point, we can go up 2 and over 1



So starting at , go up 2 units


and to the right 1 unit to get to the next point



Now draw a line through these points to graph y=2x-8

So this is the graph of y=2x-8 through the points and


Radicals/128490: Is the given function f%28x%29=x%5E2-4 one-to-one? Why or why not?

1 solutions

Answer 94016 by jim_thompson5910(28595) About Me  on 2008-02-22 17:36:30 (Show Source):
You can put this solution on YOUR website!

Notice if we graph f%28x%29=x%5E2-4, we get


+graph%28+500%2C+500%2C+-10%2C+10%2C+-10%2C+10%2C+x%5E2-4%29+



From the graph, we can see that the curve violates the horizontal line test. In other words, if you pass a straightedge horizontally through the graph, the straightedge will touch two points. So the function is not one-to-one.


Radicals/128489: Is the given function one-to-one?


+graph%28+500%2C+500%2C+-10%2C+10%2C+-10%2C+10%2C+-%28x%2B1%29%5E3-3%29+



1 solutions

Answer 94015 by jim_thompson5910(28595) About Me  on 2008-02-22 17:32:21 (Show Source):
You can put this solution on YOUR website!

Notice how the graph does not violate the horizontal or vertical line test. So this shows us that the function is one-to-one.