# Solving a System?

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• February 5th 2009, 12:06 AM
lil_cookie
Solving a System?
Hey Guys!
This is my last question of the Unit that I am planning to send in tomorrow morning.

My text does not provide me with enough examples or information to help me solve this question so I'm looking for some answers please!

Solve the following system:
2^(x+3y) =128 and 2^(3x-7)=2

(Surprised)

Thank You for any help anyone can provide to me!
• February 5th 2009, 12:12 AM
red_dog
$\left\{\begin{array}{ll}2^{x+3y}=2^7\\2^{3x-7}=2^1\end{array}\right.\Rightarrow\left\{\begin{a rray}{ll}x+3y=7\\3x-7=1\end{array}\right.$

Now you have yo solve the last system.
• February 5th 2009, 12:37 AM
lil_cookie
Thanks for the reply

That is actually as far as I got....
I don't understand what I have to do next or how to even go about this...
• February 5th 2009, 05:41 AM
Jester
Quote:

Originally Posted by red_dog
$\left\{\begin{array}{ll}2^{x+3y}=2^7\\2^{3x-7}=2^1\end{array}\right.\Rightarrow\left\{\begin{a rray}{ll}x+3y=7\\3x-7=1\end{array}\right.$

Now you have yo solve the last system.

Quote:

Originally Posted by lil_cookie
Thanks for the reply

That is actually as far as I got....
I don't understand what I have to do next or how to even go about this...

From red-dog's work, solve the second for x

$x = \frac{8}{3}$

then substitute into the first to get y.
• February 5th 2009, 07:35 AM
lil_cookie
Oh I got it

Thank you 2 (Clapping)