Question

Write a simplified polynomial expression to represent the area of the rectangle

with a x + 5 on the right side and a 2x - 4 on the bottom.

Answer 1

The answer is A = 2x² + 6x - 20
 
The area of the rectangle is:
A = l * w

l = x + 5
w = 2x - 4

A = (x + 5)(2x - 4)

Use the distributive property to calculate this:
A = (x + 5)(2x - 4)
A = x * 2x + x * (-4) + 5 * 2x + 5 * (-4)
A = 2x² - 4x + 10x  - 20
A = 2x² + 6x - 20