Prerequisites - P.3 - Polynomials and Special Products - Exercises - Page 32: 78

$1.5x^2+12x+24$

Area of the whole triangle is... $\frac{bh}{2}=\frac{(2x+8)(2x+8)}{2}=\frac{4x^2+32x+64}{2}=2x^2+16x+32$ Smaller area of the Un-shaded triangle... $\frac{bh}{2}=\frac{x^2+8x+16}{2}=0.5x^2+4x+8$ Area of the shaded region $=$ Area of the whole triangle $-$ Area of the unshaded triangle... Thus, $A=2x^2+16x+32-0.5x^2-4x-8=1.5x^2+12x+24$