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Linear-equations/246357: What is the slope of any line parallel to the line 9x + 4y = 7 ?
since 4y=-9x+7
i think its -9/4 but iam not even sure how i got that im so lost please explain it to me thanks
1 solutions

Answer 179954 by jim_thompson5910(28595) About Me  on 2009-12-06 14:39:29 (Show Source):
You can put this solution on YOUR website!

9x%2B4y=7 Start with the given equation.


4y=7-9x Subtract 9x from both sides.


4y=-9x%2B7 Rearrange the terms.


y=%28-9x%2B7%29%2F%284%29 Divide both sides by 4 to isolate y.


y=%28%28-9%29%2F%284%29%29x%2B%287%29%2F%284%29 Break up the fraction.


y=-%289%2F4%29x%2B7%2F4 Reduce.


So the equation y=-%289%2F4%29x%2B7%2F4 is now in slope intercept form y=mx%2Bb where the slope is m=-9%2F4 and the y-intercept is b=7%2F4 note: the y-intercept is the point


Trigonometry-basics/246385: Find all solutions of the equation in the interval [0,2π) algebraically. Sec^2 x - sec x =2
what are the steps to do this problem? how do i start?
1 solutions

Answer 179953 by jim_thompson5910(28595) About Me  on 2009-12-06 14:36:26 (Show Source):
You can put this solution on YOUR website!
Hint: Let z=sec%28x%29. So z%5E2=%28sec%28x%29%29%5E2 which means that the equation %28sec%28x%29%29%5E2-sec%28x%29=2 becomes z%5E2-z=2. Use the quadratic formula to solve for 'z'. Once you have the solutions in terms of z, use them to find the solutions in terms of x.


Divisibility_and_Prime_Numbers/246393: Hi! i'm having some trouble with Prime Numbers. Here is my question
Write 270 as a product of prime numbers
1 solutions

Answer 179952 by jim_thompson5910(28595) About Me  on 2009-12-06 14:34:08 (Show Source):
You can put this solution on YOUR website!
Solved by pluggable solver: Factor any number
270 is NOT a prime number: 270 = 2 * 3 * 3 * 3 * 5

Work Shown

270 is divisible by 2: 270 = 135 * 2.
135 is divisible by 3: 135 = 45 * 3.
45 is divisible by 3: 45 = 15 * 3.
15 is divisible by 3: 15 = 5 * 3.
5 is not divisible by anything.

This calculation used this Prime Factorization Algorithm.


Complex_Numbers/246256: Find the complex number z = a + bi such that z^3= 2 + 2i where a is less than or equal to 0 and b is greater than or equal to 0.
I really don't know how to approach this question but I'm guessing you have to use the definition (a + bi)(c + di) = (ac-bd)+(ad+bc)i?

1 solutions

Answer 179881 by jim_thompson5910(28595) About Me  on 2009-12-06 02:02:09 (Show Source):
You can put this solution on YOUR website!
Hint: Convert the complex number 2%2B2i into polar form z=r%28cos%28x%29%2Bi%2Asin%28x%29%29 where 'r' is the magnitude and 'x' is the angle. From there, use a variation of De Moivre's Theorem. Let me know if this helps or not.


Probability-and-statistics/246255: Compute each of the following. Look for simplifications first.
a. 20P15 (the 20 and the 15 are small)It's looking for the permutation??
b. (n+1)!
------
(n-1)!
Thank you so much in advance.
This is so difficult.
~Marney


1 solutions

Answer 179880 by jim_thompson5910(28595) About Me  on 2009-12-06 01:58:40 (Show Source):
You can put this solution on YOUR website!
a)


n%21%2F%28n-r%29%21 Start with the given formula



20%21%2F%2820-15%29%21 Plug in n=20 and r=15



20%21%2F5%21 Subtract 20-15 to get 5



Expand 20!




Expand 5!




Cancel



20%2A19%2A18%2A17%2A16%2A15%2A14%2A13%2A12%2A11%2A10%2A9%2A8%2A7%2A6 Simplify




20274183401472000 Now multiply 20*19*18*17*16*15*14*13*12*11*10*9*8*7*6 to get 20,274,183,401,472,000



================================================================
b)

... Start with the given expression.


... Expand the numerator. Remember that n! = n(n-1)(n-2)(n-3)...(3)(2)(1). So (n+1)! = (n+1)(n+1-1)(n+1-2)(n+1-3)(n+1-4)...(3)(2)(1)



... Combine like terms.


... Take note that (n-1)! = (n-1)(n-2)(n-3)...(3)(2)(1) which is what the numerator (minus the first two terms) looks like. So rewrite (n-1)(n-2)(n-3)...(3)(2)(1) as (n-1)!


Note: if you're asking 'Why did we just do that?' The goal is to cancel out the factorials. Since the denominator has a (n-1)! term, we just need that term in the numerator for it to cancel out.


... Cancel out the common terms.


... Rearrange the terms.


... Distribute


So where 'n' is an integer and n%3E=1


Graphs/246061: Solve each system by addition
x+y = 7
x-y =9
1 solutions

Answer 179768 by jim_thompson5910(28595) About Me  on 2009-12-05 14:15:16 (Show Source):
You can put this solution on YOUR website!

Start with the given system of equations:
system%28x%2By=7%2Cx-y=9%29


Add the equations together. You can do this by simply adding the two left sides and the two right sides separately like this:


%28x%2By%29%2B%28x-y%29=%287%29%2B%289%29


%28x%2Bx%29%2B%28y-y%29=7%2B9 Group like terms.


2x%2B0y=16 Combine like terms.


2x=16 Simplify.


x=%2816%29%2F%282%29 Divide both sides by 2 to isolate x.


x=8 Reduce.


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


x%2By=7 Now go back to the first equation.


8%2By=7 Plug in x=8.


y=7-8 Subtract 8 from both sides.


y=-1 Combine like terms on the right side.


So the solutions are x=8 and y=-1.


Which form the ordered pair .


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=7 (red) and x-y=9 (green)


Functions/246034: consider the functions f(x)=-x^2+3x+10 and g(x)=2x^2+2x+11/4. what is the exact distance between the vertices of the graphs of these two functions? cannot use graphing to answer.
hopefully this will be my last question of the year.
1 solutions

Answer 179698 by jim_thompson5910(28595) About Me  on 2009-12-05 02:01:55 (Show Source):
You can put this solution on YOUR website!
Part 1) Find the vertices of f%28x%29=-x%5E2%2B3x%2B10 and g%28x%29=2x%5E2%2B2x%2B11%2F4

part a) Let's find the vertex of f%28x%29=-x%5E2%2B3x%2B10



In order to find the vertex, we first need to find the x-coordinate of the vertex.


To find the x-coordinate of the vertex, use this formula: x=%28-b%29%2F%282a%29.


x=%28-b%29%2F%282a%29 Start with the given formula.


From y=-x%5E2%2B3x%2B10, we can see that a=-1, b=3, and c=10.


x=%28-%283%29%29%2F%282%28-1%29%29 Plug in a=-1 and b=3.


x=%28-3%29%2F%28-2%29 Multiply 2 and -1 to get -2.


x=3%2F2 Reduce.


So the x-coordinate of the vertex is x=3%2F2. Note: this means that the axis of symmetry is also x=3%2F2.


Now that we know the x-coordinate of the vertex, we can use it to find the y-coordinate of the vertex.


y=-x%5E2%2B3x%2B10 Start with the given equation.


y=-%283%2F2%29%5E2%2B3%283%2F2%29%2B10 Plug in x=3%2F2.


y=-1%289%2F4%29%2B3%283%2F2%29%2B10 Square 3%2F2 to get 9%2F4.


y=-9%2F4%2B3%283%2F2%29%2B10 Multiply -1 and 9%2F4 to get -9%2F4.


y=-9%2F4%2B9%2F2%2B10 Multiply 3 and 3%2F2 to get 9%2F2.


y=49%2F4 Combine like terms.


So the y-coordinate of the vertex is y=49%2F4.


So the vertex is .


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

b) Now let's find the vertex of g%28x%29=2x%5E2%2B2x%2B11%2F4




In order to find the vertex, we first need to find the x-coordinate of the vertex.


To find the x-coordinate of the vertex, use this formula: x=%28-b%29%2F%282a%29.


x=%28-b%29%2F%282a%29 Start with the given formula.


From y=2x%5E2%2B2x%2B11%2F4, we can see that a=2, b=2, and c=11%2F4.


x=%28-%282%29%29%2F%282%282%29%29 Plug in a=2 and b=2.


x=%28-2%29%2F%284%29 Multiply 2 and 2 to get 4.


x=-1%2F2 Reduce.


So the x-coordinate of the vertex is x=-1%2F2. Note: this means that the axis of symmetry is also x=-1%2F2.


Now that we know the x-coordinate of the vertex, we can use it to find the y-coordinate of the vertex.


y=2x%5E2%2B2x%2B11%2F4 Start with the given equation.


y=2%28-1%2F2%29%5E2%2B2%28-1%2F2%29%2B11%2F4 Plug in x=-1%2F2.


y=2%281%2F4%29%2B2%28-1%2F2%29%2B11%2F4 Square -1%2F2 to get 1%2F4.


y=1%2F2%2B2%28-1%2F2%29%2B11%2F4 Multiply 2 and 1%2F4 to get 1%2F2.


y=1%2F2-1%2B11%2F4 Multiply 2 and -1%2F2 to get -1.


y=9%2F4 Combine like terms.


So the y-coordinate of the vertex is y=9%2F4.


So the vertex is .


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


So to recap, the vertices of f%28x%29=-x%5E2%2B3x%2B10 and g%28x%29=2x%5E2%2B2x%2B11%2F4 are and respectively.


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

Part 2) Now use the distance formula to find the distance between the two vertices (which are essentially points)



Note: is the first point . So this means that x%5B1%5D=3%2F2 and y%5B1%5D=49%2F4.
Also, is the second point . So this means that x%5B2%5D=-1%2F2 and y%5B2%5D=9%2F4.



d=sqrt%28%28x%5B1%5D-x%5B2%5D%29%5E2%2B%28y%5B1%5D-y%5B2%5D%29%5E2%29 Start with the distance formula.


d=sqrt%28%283%2F2--1%2F2%29%5E2%2B%2849%2F4-9%2F4%29%5E2%29 Plug in x%5B1%5D=3%2F2, x%5B2%5D=-1%2F2, y%5B1%5D=49%2F4, and y%5B2%5D=9%2F4.


d=sqrt%28%282%29%5E2%2B%2849%2F4-9%2F4%29%5E2%29 Subtract -1%2F2 from 3%2F2 to get 3%2F2--1%2F2=4%2F2=2.


d=sqrt%28%282%29%5E2%2B%2810%29%5E2%29 Subtract 9%2F4 from 49%2F4 to get 49%2F4-9%2F4=40%2F4=10.


d=sqrt%284%2B%2810%29%5E2%29 Square 2 to get 4.


d=sqrt%284%2B100%29 Square 10 to get 100.


d=sqrt%28104%29 Add 4 to 100 to get 104.


d=2%2Asqrt%2826%29 Simplify the square root.


So our answer is d=2%2Asqrt%2826%29


So the exact distance between the two vertices is 2%2Asqrt%2826%29 units.


Polynomials-and-rational-expressions/245969: I was wondering if you could show me how to factor this equation: 7a2+53a+28
This is the work I got to but then I could go no father.
I used the x-box to find the answer.
After the x-box I got
(a+7)(7a+7)
7a2+56a+28 which does not equal the original question.
(when it says 7a2 it means 7 times a squared)
1 solutions

Answer 179649 by jim_thompson5910(28595) About Me  on 2009-12-04 18:40:11 (Show Source):
You can put this solution on YOUR website!

Looking at the expression 7a%5E2%2B53a%2B28, we can see that the first coefficient is 7, the second coefficient is 53, and the last term is 28.


Now multiply the first coefficient 7 by the last term 28 to get %287%29%2828%29=196.


Now the question is: what two whole numbers multiply to 196 (the previous product) and add to the second coefficient 53?


To find these two numbers, we need to list all of the factors of 196 (the previous product).


Factors of 196:
1,2,4,7,14,28,49,98,196
-1,-2,-4,-7,-14,-28,-49,-98,-196


Note: list the negative of each factor. This will allow us to find all possible combinations.


These factors pair up and multiply to 196.
1*196 = 196
2*98 = 196
4*49 = 196
7*28 = 196
14*14 = 196
(-1)*(-196) = 196
(-2)*(-98) = 196
(-4)*(-49) = 196
(-7)*(-28) = 196
(-14)*(-14) = 196

Now let's add up each pair of factors to see if one pair adds to the middle coefficient 53:


First NumberSecond NumberSum
11961+196=197
2982+98=100
4494+49=53
7287+28=35
141414+14=28
-1-196-1+(-196)=-197
-2-98-2+(-98)=-100
-4-49-4+(-49)=-53
-7-28-7+(-28)=-35
-14-14-14+(-14)=-28



From the table, we can see that the two numbers 4 and 49 add to 53 (the middle coefficient).


So the two numbers 4 and 49 both multiply to 196 and add to 53


Now replace the middle term 53a with 4a%2B49a. Remember, 4 and 49 add to 53. So this shows us that 4a%2B49a=53a.


7a%5E2%2Bhighlight%284a%2B49a%29%2B28 Replace the second term 53a with 4a%2B49a.


%287a%5E2%2B4a%29%2B%2849a%2B28%29 Group the terms into two pairs.


a%287a%2B4%29%2B%2849a%2B28%29 Factor out the GCF a from the first group.


a%287a%2B4%29%2B7%287a%2B4%29 Factor out 7 from the second group. The goal of this step is to make the terms in the second parenthesis equal to the terms in the first parenthesis.


%28a%2B7%29%287a%2B4%29 Combine like terms. Or factor out the common term 7a%2B4


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


Answer:


So 7a%5E2%2B53a%2B28 factors to %28a%2B7%29%287a%2B4%29.


In other words, 7a%5E2%2B53a%2B28=%28a%2B7%29%287a%2B4%29.


Note: you can check the answer by expanding %28a%2B7%29%287a%2B4%29 to get 7a%5E2%2B53a%2B28 or by graphing the original expression and the answer (the two graphs should be identical).


Trigonometry-basics/245808: Use Descartes' Rule of Sign to determine how many positive and negative zeros each polynomial function may have.
f%28x%29+=+-6x%5E5+%2B+x%5E4+%2B+5x%5E3+%2B+x+%2B+1
1 solutions

Answer 179612 by jim_thompson5910(28595) About Me  on 2009-12-04 16:08:26 (Show Source):
You can put this solution on YOUR website!

First count the sign changes of f%28x%29=-6x%5E5%2Bx%5E4%2B5x%5E3%2Bx%2B1

From -6x%5E5 to x%5E4, there is a sign change from negative to positive

From x%5E4 to 5x%5E3, there is no change in sign

From 5x%5E3 to x, there is no change in sign

From x to 1, there is no change in sign

So there is 1 sign change for the expression f%28x%29=-6x%5E5%2Bx%5E4%2B5x%5E3%2Bx%2B1.

So there is 1 positive zero.



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

f%28-x%29=-6%28-x%29%5E5%2B%28-x%29%5E4%2B5%28-x%29%5E3%2B%28-x%29%2B1 Now let's replace each x with -x


f%28-x%29=6x%5E5%2Bx%5E4-5x%5E3-x%2B1 Simplify


Now let's count the sign changes of f%28-x%29=6x%5E5%2Bx%5E4-5x%5E3-x%2B1

From 6x%5E5 to x%5E4, there is no change in sign

From x%5E4 to -5x%5E3, there is a sign change from positive to negative

From -5x%5E3 to -x, there is no change in sign

From -x to 1, there is a sign change from negative to positive

So there are 2 sign changes for the expression f%28-x%29=6x%5E5%2Bx%5E4-5x%5E3-x%2B1.

So there are 2 or 0 negative zeros


Systems-of-equations/245919: Is each equation a direct variation? If it is, find the constant of variation.
y=5x
1 solutions

Answer 179610 by jim_thompson5910(28595) About Me  on 2009-12-04 16:01:54 (Show Source):
You can put this solution on YOUR website!
Yes it is an equation of direct variation since it is of the form y=kx where 'k' is the constant of variation. Looking at the equation, we see that the constant of variation is k=5


Square-cubic-other-roots/245743: how do u factor x^3+64 and what are the roots of the polynomials?
1 solutions

Answer 179466 by jim_thompson5910(28595) About Me  on 2009-12-04 00:28:26 (Show Source):
You can put this solution on YOUR website!

x%5E3%2B64 Start with the given expression.


%28x%29%5E3%2B%284%29%5E3 Rewrite x%5E3 as %28x%29%5E3. Rewrite 64 as %284%29%5E3.


%28x%2B4%29%28%28x%29%5E2-%28x%29%284%29%2B%284%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


%28x%2B4%29%28x%5E2-4x%2B16%29 Multiply

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

So x%5E3%2B64 factors to %28x%2B4%29%28x%5E2-4x%2B16%29.


In other words, x%5E3%2B64=%28x%2B4%29%28x%5E2-4x%2B16%29


So to find the roots of x%5E3%2B64, just find the roots of %28x%2B4%29%28x%5E2-4x%2B16%29. In other words, solve the equation:


%28x%2B4%29%28x%5E2-4x%2B16%29=0


Quadratic_Equations/245751: I need to find the zeros of f(x)=x^2+2ix-3.
I tried using the quadratic equation, but the i is confusing me.
Help?
1 solutions

Answer 179460 by jim_thompson5910(28595) About Me  on 2009-12-04 00:03:34 (Show Source):
You can put this solution on YOUR website!
Just treat this quadratic as you normally would, but make sure to follow the rules of complex arithmetic.


x%5E2%2B2ix-3=0 Start with the given equation.


Notice that the quadratic x%5E2%2B2ix-3 is in the form of Ax%5E2%2BBx%2BC where A=1, B=2i, and C=-3


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-%282i%29+%2B-+sqrt%28+%282i%29%5E2-4%281%29%28-3%29+%29%29%2F%282%281%29%29 Plug in A=1, B=2i, and C=-3


x+=+%28-2i+%2B-+sqrt%28+-4-4%281%29%28-3%29+%29%29%2F%282%281%29%29 Square 2i to get %282i%29%5E2=%282i%29%282i%29=4i%5E2=4%28-1%29=-4


Note: Since i=sqrt%28-1%29, i%5E2=%28sqrt%28-1%29%29%5E2=-1


x+=+%28-2i+%2B-+sqrt%28+-4%2B12+%29%29%2F%282%281%29%29 Multiply -4, 1 and -3 to get -4%281%29%28-3%29=12


x+=+%28-2i+%2B-+sqrt%28+-4%2B12+%29%29%2F%282%29 Multiply 2 and 1 to get 2.


x+=+%28-2i+%2B-+sqrt%28+8+%29%29%2F%282%29 Combine like terms.


x+=+%28-2i+%2B-+2%2Asqrt%28+2+%29%29%2F%282%29 Simplify the square root.


x+=+-i+%2B-+sqrt%28+2+%29 Reduce.


x+=+-i+%2B+sqrt%28+2+%29 or x+=+-i+-+sqrt%28+2+%29 Break up the 'plus/minus'


So the solutions are x+=+-i+%2B+sqrt%28+2+%29 or x+=+-i+-+sqrt%28+2+%29


Equations/245698: solve:
9/5=3x+9/15
1 solutions

Answer 179414 by jim_thompson5910(28595) About Me  on 2009-12-03 21:05:35 (Show Source):
You can put this solution on YOUR website!

9%2F5=3x%2B9%2F15 Start with the given equation.


15%289%2Fcross%285%29%29=15%283x%2B9%2Fcross%2815%29%29 Multiply both sides by the LCD 15 to clear any fractions.


27=45x%2B9 Distribute and multiply.


0=45x%2B9-27 Subtract 27 from both sides.


-45x=9-27 Subtract 45x from both sides.


-45x=-18 Combine like terms on the right side.


x=%28-18%29%2F%28-45%29 Divide both sides by -45 to isolate x.


x=2%2F5 Reduce.


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

Answer:

So the solution is x=2%2F5


Linear-equations/245694: I need help with this problem 2y=7, I need to change the equation to slope-intercept form. I tried dividing both sides by 2 but, I'm missing m and b. The slope-intercept form form is y=mx+b.


Thanks for your help!
Ivelisse
1 solutions

Answer 179413 by jim_thompson5910(28595) About Me  on 2009-12-03 21:04:34 (Show Source):
You can put this solution on YOUR website!
It is possible for 'm' to be equal to zero. You're on the right track. If you divide both sides by 2, you get y=7%2F2 which is in y=mx%2Bb form where m=0 and b=7%2F2. If you can't see it, then write y=7%2F2 as y=0x%2B7%2F2 (which is perfectly valid).


expressions/244936: Please simplify 6(r+1)-2+2(r-5)=
Also (x^2+3x-2)-(x^2-2x-5)=
Thanks!
1 solutions

Answer 179111 by jim_thompson5910(28595) About Me  on 2009-12-02 13:13:43 (Show Source):
You can put this solution on YOUR website!
I'll do the first one to get you started.

# 1

6%28r%2B1%29-2%2B2%28r-5%29=6r%2B6-2%2B2r-10=8r-6


So 6%28r%2B1%29-2%2B2%28r-5%29=8r-6


Exponential-and-logarithmic-functions/245000: find the inverse of log(base 2) (x^5)
when i worked it out i got 2^x^5....but i didnt know if that could be simplified any further?
1 solutions

Answer 179110 by jim_thompson5910(28595) About Me  on 2009-12-02 13:08:23 (Show Source):
You can put this solution on YOUR website!
Let y=log%282%2C%28x%5E5%29%29. Now swap x and y to get x=log%282%2C%28y%5E5%29%29. The goal here is to solve for y.


x=log%282%2C%28y%5E5%29%29 Start with the given equation.


2%5Ex=y%5E5 Convert to exponential form.


root%285%2C2%5Ex%29=y Take the 5th root of both sides to isolate 'y'


So the inverse is root%285%2C2%5Ex%29


logarithm/244987: x=12^(log base 12 of 5)
I think that's the same as:
x=12^(5 log base 12), but I'm just trying to follow previous patterns and I'm lost
1 solutions

Answer 179109 by jim_thompson5910(28595) About Me  on 2009-12-02 13:05:57 (Show Source):
You can put this solution on YOUR website!
It turns out that a%5Elog%28a%2C%28b%29%29=log%28a%2C%28a%5Eb%29%29=b. In this problem, it's useful to know a%5Elog%28a%2C%28b%29%29=b.


In this case, a=12 and b=5. So x=12%5E%28log%2812%2C%285%29%29%29=5 which means that the answer is x=5


Exponential-and-logarithmic-functions/244839: 2%5E%284x%29%2A3%5Ex=100
I don't know where to start on this one.
I know it should be a log, but don't know how to set it up.
1 solutions

Answer 179004 by jim_thompson5910(28595) About Me  on 2009-12-01 22:52:21 (Show Source):
You can put this solution on YOUR website!
2%5E%284x%29%2A3%5Ex=100 Start with the given equation.


log%2810%2C%282%5E%284x%29%2A3%5Ex%29%29=log%2810%2C%28100%29%29 Take the log of both sides.


log%2810%2C%282%5E%284x%29%2A3%5Ex%29%29=2 Evaluate the log base 10 of 100 to get 2.


log%2810%2C%282%5E%284x%29%29%29%2Blog%2810%2C%283%5Ex%29%29=2 Break up the log using the identity log%28b%2C%28A%2AB%29%29=log%28b%2C%28A%29%29%2Blog%28b%2C%28B%29%29


4x%2Alog%2810%2C%282%29%29%2Bx%2Alog%2810%2C%283%29%29=2 Pull down the exponents using the identity log%28b%2C%28x%5Ey%29%29=y%2Alog%28b%2C%28x%29%29


x%284%2Alog%2810%2C%282%29%29%2Blog%2810%2C%283%29%29%29=2 Factor out the GCF 'x'


x=2%2F%284%2Alog%2810%2C%282%29%29%2Blog%2810%2C%283%29%29%29 Divide both sides by 4%2Alog%2810%2C%282%29%29%2Blog%2810%2C%283%29%29


x=2%2F%28log%2810%2C%282%5E4%29%29%2Blog%2810%2C%283%29%29%29 Place the coefficient as the exponent using the identity y%2Alog%28b%2C%28x%29%29=log%28b%2C%28x%5Ey%29%29


x=2%2F%28log%2810%2C%2816%29%29%2Blog%2810%2C%283%29%29%29 Raise 2 to the 4th power to get 16


x=2%2F%28log%2810%2C%2816%2A3%29%29%29 Combine the logs using the identity log%28b%2C%28A%29%29%2Blog%28b%2C%28B%29%29=log%28b%2C%28A%2AB%29%29


x=2%2Flog%2810%2C%2848%29%29 Multiply


So the solution is x=2%2Flog%2810%2C%2848%29%29 which approximates to x=1.18959727


Graphs/244833: My problem is 3/2,-3 0,2/5 this involves the y2-y1
x2-x2
I'm having some problems with the fractions.
1 solutions

Answer 179002 by jim_thompson5910(28595) About Me  on 2009-12-01 22:44:20 (Show Source):
You can put this solution on YOUR website!
Note: is the first point . So this means that x%5B1%5D=3%2F2 and y%5B1%5D=-3.
Also, is the second point . So this means that x%5B2%5D=0 and y%5B2%5D=2%2F5.


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


m=%282%2F5--3%29%2F%280-3%2F2%29 Plug in y%5B2%5D=2%2F5, y%5B1%5D=-3, x%5B2%5D=0, and x%5B1%5D=3%2F2


m=%2817%2F5%29%2F%280-3%2F2%29 Subtract -3 from 2%2F5 to get 2%2F5--3=2%2F5%2B3=2%2F5%2B15%2F5=%282%2B15%29%2F5=17%2F5


m=%2817%2F5%29%2F%28-3%2F2%29 Subtract 3%2F2 from 0 to get -3%2F2


m=%2817%2F5%29%2A%28-2%2F3%29 Multiply the first fraction by the reciprocal of the second fraction.


m=-34%2F15 Multiply.


So the slope of the line that goes through the points and is m=-34%2F15



Trigonometry-basics/244836: Solving trigonomic equations algebraically, in terms of pi
cot^2(x)=1
so far i got cot(x)=√1
then what?
1 solutions

Answer 179001 by jim_thompson5910(28595) About Me  on 2009-12-01 22:41:12 (Show Source):
You can put this solution on YOUR website!
Well remember that 1%5E2=1. So take the square root of both sides to get 1=sqrt%281%29. So taking the square root of 1 is just 1.

This gets you: cot%28x%29=1.


1%2Ftan%28x%29=1 Now use the identity cot%28x%29=1%2Ftan%28x%29


1=tan%28x%29 Multiply both sides by tan(x)


So tan%28x%29=1. Can you solve it from here? You'll need to use the unit circle if you're not familiar with all of the trig values.


Equations/244834: A person has quarters, dimes, nickels,and pennies with a total value of $3.86. The number of nickels is twice the number of quarters. The number of quarters is two less than the number of dimes. There are 40 coins in all. Write and solve an equation to find the number of each coin. I have figured out that there are eight quarters, sixteen nickels, ten dimes, and six pennies. I can not figure out how to write an equation for this problem. Can you help me?
1 solutions

Answer 178999 by jim_thompson5910(28595) About Me  on 2009-12-01 22:38:22 (Show Source):
You can put this solution on YOUR website!
Let

p = # of pennies,
n = # of nickels
d = # of dimes
q = # of quarters


Since "There are 40 coins in all", this means that p%2Bn%2Bd%2Bq=40 (ie add up the individual coin counts to get the total). This is your first equation.

Because "The number of nickels is twice the number of quarters", we know that n=2q

Since "The number of quarters is two less than the number of dimes", we also know that q=d-2

Finally, because "A person has quarters, dimes, nickels,and pennies with a total value of $3.86", we get the equation 0.01p%2B0.05n%2B0.10d%2B0.25q=3.86

Remember that a penny is $0.01, a nickel is $0.05, a dime is $0.10, and a quarter is $0.25. If you multiply those individual values by their counts (the defined variables) and add them all up, you'll get the total coin value $3.86


So the fourth and final equation is 0.01p%2B0.05n%2B0.10d%2B0.25q=3.86


At the end of the translations, you get the four equations


system%28p%2Bn%2Bd%2Bq=40%2Cn=2q%2Cq=d-2%2C0.01p%2B0.05n%2B0.10d%2B0.25q=3.86%29


From here, all you need to do is solve the system. There are plenty of options available, but I recommend using a calculator to set up a matrix to solve this problem.


Quadratic_Equations/244806: For the following equation, state the value of the discriminant and then describe the nature of the solutions.
2x^2-10x-12=0
What is the value of the discriminant?
Which one of the statements below is correct?
a. The equation has two imaginary solutions.
b. The equation has two real solutions.
c. The equation has one real solution?
Thanks for your help!
1 solutions

Answer 178995 by jim_thompson5910(28595) About Me  on 2009-12-01 22:26:13 (Show Source):
You can put this solution on YOUR website!

From 2x%5E2-10x-12 we can see that a=2, b=-10, and c=-12


D=b%5E2-4ac Start with the discriminant formula.


D=%28-10%29%5E2-4%282%29%28-12%29 Plug in a=2, b=-10, and c=-12


D=100-4%282%29%28-12%29 Square -10 to get 100


D=100--96 Multiply 4%282%29%28-12%29 to get %288%29%28-12%29=-96


D=100%2B96 Rewrite D=100--96 as D=100%2B96


D=196 Add 100 to 96 to get 196


Since the discriminant is greater than zero, this means that there are two real solutions.


expressions/244776: can you help me simplify
x^2-6x+8/x-3
1 solutions

Answer 178994 by jim_thompson5910(28595) About Me  on 2009-12-01 22:25:06 (Show Source):
You can put this solution on YOUR website!
Check out this page for the solution.


Equations/244754: how do I solve the problem 4k-3k+7=-13?
1 solutions

Answer 178993 by jim_thompson5910(28595) About Me  on 2009-12-01 22:21:49 (Show Source):
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4k-3k%2B7=-13 Start with the given equation.


k%2B7=-13 Combine like terms on the left side.


k=-13-7 Subtract 7 from both sides.


k=-20 Combine like terms on the right side.


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

Answer:

So the solution is k=-20


Expressions-with-variables/244746: How i solve this problem 10x^2-19x+6
1 solutions

Answer 178991 by jim_thompson5910(28595) About Me  on 2009-12-01 22:21:03 (Show Source):
You can put this solution on YOUR website!
I'm assuming that you want to factor this.



Looking at the expression 10x%5E2-19x%2B6, we can see that the first coefficient is 10, the second coefficient is -19, and the last term is 6.


Now multiply the first coefficient 10 by the last term 6 to get %2810%29%286%29=60.


Now the question is: what two whole numbers multiply to 60 (the previous product) and add to the second coefficient -19?


To find these two numbers, we need to list all of the factors of 60 (the previous product).


Factors of 60:
1,2,3,4,5,6,10,12,15,20,30,60
-1,-2,-3,-4,-5,-6,-10,-12,-15,-20,-30,-60


Note: list the negative of each factor. This will allow us to find all possible combinations.


These factors pair up and multiply to 60.
1*60 = 60
2*30 = 60
3*20 = 60
4*15 = 60
5*12 = 60
6*10 = 60
(-1)*(-60) = 60
(-2)*(-30) = 60
(-3)*(-20) = 60
(-4)*(-15) = 60
(-5)*(-12) = 60
(-6)*(-10) = 60

Now let's add up each pair of factors to see if one pair adds to the middle coefficient -19:


First NumberSecond NumberSum
1601+60=61
2302+30=32
3203+20=23
4154+15=19
5125+12=17
6106+10=16
-1-60-1+(-60)=-61
-2-30-2+(-30)=-32
-3-20-3+(-20)=-23
-4-15-4+(-15)=-19
-5-12-5+(-12)=-17
-6-10-6+(-10)=-16



From the table, we can see that the two numbers -4 and -15 add to -19 (the middle coefficient).


So the two numbers -4 and -15 both multiply to 60 and add to -19


Now replace the middle term -19x with -4x-15x. Remember, -4 and -15 add to -19. So this shows us that -4x-15x=-19x.


10x%5E2%2Bhighlight%28-4x-15x%29%2B6 Replace the second term -19x with -4x-15x.


%2810x%5E2-4x%29%2B%28-15x%2B6%29 Group the terms into two pairs.


2x%285x-2%29%2B%28-15x%2B6%29 Factor out the GCF 2x from the first group.


2x%285x-2%29-3%285x-2%29 Factor out 3 from the second group. The goal of this step is to make the terms in the second parenthesis equal to the terms in the first parenthesis.


%282x-3%29%285x-2%29 Combine like terms. Or factor out the common term 5x-2


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


Answer:


So 10x%5E2-19x%2B6 factors to %282x-3%29%285x-2%29.


In other words, 10x%5E2-19x%2B6=%282x-3%29%285x-2%29.


Note: you can check the answer by expanding %282x-3%29%285x-2%29 to get 10x%5E2-19x%2B6 or by graphing the original expression and the answer (the two graphs should be identical).


Linear-systems/244750: 3x-5y=-3,-9x-15y=9 how do you solve using the elimination method?
1 solutions

Answer 178990 by jim_thompson5910(28595) About Me  on 2009-12-01 22:20:09 (Show Source):
You can put this solution on YOUR website!

Start with the given system of equations:
system%283x-5y=-3%2C-9x-15y=9%29


3%283x-5y%29=3%28-3%29 Multiply the both sides of the first equation by 3.


9x-15y=-9 Distribute and multiply.


So we have the new system of equations:
system%289x-15y=-9%2C-9x-15y=9%29


Now add the equations together. You can do this by simply adding the two left sides and the two right sides separately like this:


%289x-15y%29%2B%28-9x-15y%29=%28-9%29%2B%289%29


%289x%2B-9x%29%2B%28-15y%2B-15y%29=-9%2B9 Group like terms.


0x%2B-30y=0 Combine like terms.


-30y=0 Simplify.


y=%280%29%2F%28-30%29 Divide both sides by -30 to isolate y.


y=0 Reduce.


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


9x-15y=-9 Now go back to the first equation.


9x-15%280%29=-9 Plug in y=0.


9x=-9 Multiply.


x=%28-9%29%2F%289%29 Divide both sides by 9 to isolate x.


x=-1 Reduce.


So the solutions are x=-1 and y=0.


Which form the ordered pair .


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-5y=-3 (red) and -9x-15y=9 (green)


Radicals/244805: How would I simplify ^5√√3?
1 solutions

Answer 178984 by jim_thompson5910(28595) About Me  on 2009-12-01 22:13:53 (Show Source):
You can put this solution on YOUR website!
root%285%2Csqrt%283%29%29 Start with the given expression.


root%285%2C3%5E%281%2F2%29%5E%27%27%29 Rewrite sqrt%283%29 as 3%5E%281%2F2%29%5E%27%27 using the property sqrt%28x%29=%28x%29%5E%281%2F2%29%5E%27%27


%283%5E%281%2F2%29%29%5E%281%2F5%29 Convert root%285%2C3%5E%281%2F2%29%5E%27%27%29 to %283%5E%281%2F2%29%29%5E%281%2F5%29 using the property root%283%2Cx%29=%28x%29%5E%281%2F3%29%5E%27%27


3%5E%28%281%2F2%29%2A%281%2F5%29%29%5E%27%27 Multiply the exponents using the idea that %28x%5Ey%29%5Ez=x%5E%28yz%29


3%5E%28%281%2A1%29%2F%282%2A5%29%29%5E%27%27 Combine the fractions.


3%5E%281%2F10%29%5E%27%27 Multiply


root%2810%2C3%29 Convert back to radical notation


So root%285%2Csqrt%283%29%29=root%2810%2C3%29


Graphs/244814: find the slope of the line passing through (2,-4) AND (7,3)
1 solutions

Answer 178983 by jim_thompson5910(28595) About Me  on 2009-12-01 22:10:53 (Show Source):
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Note: is the first point . So this means that x%5B1%5D=2 and y%5B1%5D=-4.
Also, is the second point . So this means that x%5B2%5D=7 and y%5B2%5D=3.


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


m=%283--4%29%2F%287-2%29 Plug in y%5B2%5D=3, y%5B1%5D=-4, x%5B2%5D=7, and x%5B1%5D=2


m=%287%29%2F%287-2%29 Subtract -4 from 3 to get 7


m=%287%29%2F%285%29 Subtract 2 from 7 to get 5


So the slope of the line that goes through the points and is m=7%2F5


Sequences-and-series/244819: Write an expression for the apparent nth term of the sequence. (Assume n begins with 1.)
5/2, 6/5, 7/8, 8/11, 9/14, ...
How do you do this?
1 solutions

Answer 178981 by jim_thompson5910(28595) About Me  on 2009-12-01 22:09:16 (Show Source):
You can put this solution on YOUR website!
Hint: Look at the sequences of the numerators and denominators separately


Sequence of numerators: 5, 6, 7, 8, 9, ...
Sequence of denominators: 2, 5, 8, 11, 14, ...


Do you see the patterns? If not, then repost or let me know.


expressions/244747: what is equal to 5a+8-2(a+4)

1 solutions

Answer 178969 by jim_thompson5910(28595) About Me  on 2009-12-01 21:31:30 (Show Source):


Subset/244742: Let Set 1 be the entire alphabet. Let Set 2 = {u, v, w, x, y, z}
a. What is the complement of Set 2 in Set 1?
b. Set 3 = {v, w, x, y}. Is Set 3 a proper subset of Set 2? Explain your reasoning

1 solutions

Answer 178967 by jim_thompson5910(28595) About Me  on 2009-12-01 21:28:52 (Show Source):
You can put this solution on YOUR website!
a) The complement of Set 2 in Set 1 is simply the set of every letter BUT the letters u, v, w, x, y, z are NOT in the set. So write out Set 1, then cross out those letters to form the complement of Set 2 in Set 1.


b) The question you should first ask is: Is set 3 a subset of set 2? All you need to do is see if every element of set 3 is in set 2. Since v, w, x, y (elements of set 3) are all members of set 2, this means that set 3 is indeed a subset of set 2. Because there are fewer elements in set 3 than set 2, this means that set 3 is a proper subset of set 2.