Question

In terms of x, find an expression that represents the area of the shaded region. The outer square has side lengths of (x+5) and the inner square has side lengths of (x-2), as shown.

Answer 1

= (x+5)² = x² + 10x + 25

= (x-2)² = x² - 4x + 4

= (x² + 10x + 25) - (x² - 4x + 4)

= x² + 10x + 25 - x² + 4x - 4

= 14x + 21 square units