Answer:
area of square= (side)^2
area = (x+1)^2 = x^2 + 2x + 1
area of rectangle = l*b = (x+10)*(2x+5) =2x^2 + 5x + 20x + 50 = 2x^2 +25x + 50
area of shaded region = area of rectangle - area of square
= 2x^2 + 25x + 50 - (x^2 + 2x + 1) = 2x^2 + 25x + 50 - x^2 -2x -1
= x^2 + 23x + 49
