Given:
Consider the equation is

To find:
The value of x.
Solution:
We have,

Using properties of exponents, we get
![[\because \dfrac{a^m}{a^n}=a^{m-n},a^{-n}=\dfrac{1}{a^n}]](https://tex.z-dn.net/?f=%5B%5Cbecause%20%5Cdfrac%7Ba%5Em%7D%7Ba%5En%7D%3Da%5E%7Bm-n%7D%2Ca%5E%7B-n%7D%3D%5Cdfrac%7B1%7D%7Ba%5En%7D%5D)
On comparing both sides, we get

Add 16 on both sides.


Multiply both sides by -1.

Therefore, the value of x is 8.
50$ per month for 12 years would mean she spent only (50 x 12) 600$ per year.
She actually spent $711, her forecast was off target by (600-7111) $111.
She exceeded her budget by $111