area of the whole figure
= (x + 1)(2x + 3)
= x(2x + 3) + 1(2x + 3)
= 2 {x}^{2} + 3x + 2x + 3
= (2x)^(2} + 5x + 3
area of the unshaded region
= x(2x)
= 2x²
area of the shaded region
= 2x² + 5x + 3 - 2x²
= (2x² - 2x² ) + 5x + 3
= 5x+ 3
THEREFORE,
THE AREA OF THE FRAME IS C. 5x + 3