What’s the area of the original square

Question

If two opposite sides of the square are increased by 12 meters and the other sides are decreased by 7 meters ,the area of the rectangle that is formed is 66 square meter, Find the area of the original square

Answer 1

A = lw

A = (s + 12)(s - 7) = 66

s^2 + 5s - 84 = 66

s^2 + 5s -150 = 0

(s -10)(s + 15) = 0 (by inspection)

s = 10, s = 15 (disregard negative root)

s^2 = 100