# Need Help with These Exponential Equations

• May 13th 2012, 02:22 PM
Reiper
Need Help with These Exponential Equations
Hello there!
I recently enrolled in a high school math course needed to take a college course, but I was always dreadful at math, and this is a correspondence course with minimal student assistance.

I am having some difficulties, and would like help with two question

1)

(3x4*y5*z7)5
___________
(-3x3*yz4)7

For this question I got
y18z7
_____
9x

However I think I am wrong. The next question I found even more confusing

2)

(xa+b)a-b
_________

(xa-2b)a+2b

for this one I got 1/-4 but again, i think I am very lose
• May 13th 2012, 05:25 PM
Prove It
Re: Need Help with These Exponential Equations
Quote:

Originally Posted by Reiper
Hello there!
I recently enrolled in a high school math course needed to take a college course, but I was always dreadful at math, and this is a correspondence course with minimal student assistance.

I am having some difficulties, and would like help with two question

1)

(3x4*y5*z7)5
___________
(-3x3*yz4)7

For this question I got
y18z7
_____
9x

However I think I am wrong. The next question I found even more confusing

2)

(xa+b)a-b
_________

(xa-2b)a+2b

for this one I got 1/-4 but again, i think I am very lose

You are close with the first, just remember that \displaystyle \begin{align*} (-3)^7 = -3^7 \end{align*}, so your answer should be negated.

I'm afraid you're not even close with the second. You need to use the following: \displaystyle \begin{align*} \left(a^p\right)^q = a^{pq} \end{align*} and \displaystyle \begin{align*} \frac{a^{m}}{a^n} = a^{m - n} \end{align*}
• May 14th 2012, 08:36 AM
Reiper
Re: Need Help with These Exponential Equations
(xa+b)a-b

so here is what I am not getting, why do you not just multiply the exponents? IE (a+b)(a-b) = (a2-b2)
and if I do (xa+b) = (xaxb, then where do I go from there with the exponents outside the bracket?

could someone show me what step 2 and three of this question would look like?
• May 14th 2012, 08:57 AM
skeeter
Re: Need Help with These Exponential Equations
$\frac{(x^{a+b})^{a-b}}{(x^{a-2b})^{a+2b}}$

$\frac{x^{a^2-b^2}}{x^{a^2-4b^2}}$

$x^{(a^2-b^2) - (a^2-4b^2)}$

$x^{3b^2}$