Answer:
4 x 5
Step-by-step explanation:

Simplify
to 

Both are over 11, so, just sum.


1)
Area of bigger rectangle
A = (x+1)(x+1) = x^2 + 2x + 1
2)
Area of smaller rectangle
A = 5(x - 7) = 5x - 35
3)
The difference:
(x^2 + 2x + 1) - (5x - 35)
= x^2 + 2x + 1 - 5x +35
= x^2 - 3x + 36
area of the shaded region = x^2 - 3x + 36