Prerequisites - P.3 - Polynomials and Special Products - Exercises - Page 32: 77

$15x^2+18x+3$

Let A be the area of the bigger rectangle, Hence A = $(4x+2)^2 = 16x^2+16x+4$ Let B be the area of the smaller rectangle, Hence B = $(x-1)^2 = x^2-2x+1$ Subtract B from A to find the area of the shaded region. Answer = A - B = $(16x^2+16x+4) - (x^2-2x+1) = 15x^2+18x+3$