Is 1 a real or an imaginary number?

Which geometric principle is used to justify the construction below?

A)a square brown tarp has a square green patch green in the corner the side length of the tarp is (x + 8) and the side length of the patch is x what is the area of the brown part of the tarpb)a square red placemat has a gold square in the corner the side length of the gold square is (x - 2) inches with the width of the red region is 4 in what is the area of the red part of the placemat

(fog)(x) if f(x)=x^2- 4 and g(x)=x^2 + 2 x, f(g(x))= f(x^2+2x) (x^2+2x)^2-4 (x^2+2x)(x^2+2x)-4 (x^4+2x^3+5x+4x^2)-4 x^4+2x^3+4x^2+5x-4 what am i doing wrong