Let
x---------> the thickness of the frame in feet
At-------> Area of the mirror and the frame in square feet
we know that
------> equation 
--------> equation 
equate equation
and equation 

therefore
the answer is the option

Answer:
+2
Step-by-step explanation:
+ and - cancel. We have 5 + and 3 - so that leaves us with 2 + so the answer is +2.
I think it would be (x+7)/7
follow the above steps may be it's right