Question

Which polynomial, written in simplified form, represents the area of this rectangle?

Answer 1

a. 8x2-36xy-20y2
b. 8x2+22xy-20y2
c. 16x2+72xy-40y2
d. 8x2+36xy-20y2
Please show your work on how you got this.
By the way here is the rectangle

Answer 2

Area of rectangle = length * breadth/width
here length = 8x - 4y and breadth = x + 5y

so area of rectangle = (8x - 4y)(x + 5y)
= 8x(x + 5y) - 4y(x + 5y)
= 8x^2 + 40xy - 4xy - 20y^2
= 8x^2 + 36xy - 20y^2

so d) is the right answer