Answer:
38x^2 - 12x
Explanation:
To find the area of the shaded region, take the area of the large rectangle and subtract the area of the unshaded rectangle
Area large rectangle
(8x-1) * 6x = 48x^2 -6x
Area unshaded rectangle
(5x+3) * 2x = 10x^2 +6x
Subtract
A large rectangle - A unshaded rectangle
48x^2 -6x - (10x^2 +6x)
Distribute the minus sign
48x^2 -6x - 10x^2 -6x
38x^2 - 12x