Hello!
You first have to find the area of the bigger rectangle
You find this by multiplying the sides
(x + 1)(x + 1) = x^2 + 2x + 1
Next you have to find the area of the smaller rectangle
(x - 7) * 5 = 5x - 35
Subtract the two polynomials
(x^2 + 2x + 1) - (5x - 35) = x^2 - 3x + 36
The answer is

Hope this helps!