Answer:
[tex]x^2+8x+29[/tex]
Step-by-step explanation:
The shaded area is the large rectangle, minus the smaller rectangle.
Let's calculate both and simplify as much as possible
[tex](x+4)(x+8)-(x+1)(x+3) =x^2+12x+32 -(x^2+4x+3) =\\x^2+12x+32-x^2-4x-3 = x^2+8x+29[/tex]
