Ithink this answer is 18 units , am i correct ?

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

Sanderson is having trouble with his assignment. his shown work is as follows: − 3 7 7 3 = − 3 7 × 7 3 = − 21 21 = −1 however, his answer does not match the answer that his teacher gives him. complete the description of sanderson's mistake. find the correct answer.

Given: prst square pmkd is a square pr = a, pd = a find the area of pmct.