#### Answer

$15x^2+18x+3$

#### Work Step by Step

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 = $(16x^2+16x+4) - (x^2-2x+1) = 15x^2+18x+3$