What is the perimeter of the rectangle whose area = x^2+3x-40?

Perimeter = 4x + 6

Step-by-step explanation:

The area of a rectangle is given by:

Area = L * W

Where L is the length and W is the width.

In this case, we need to factorate the area to find L and W:

Area = x^2+3x-40

Making Area = (x + a) * (x + b), we have:

a * b = - 40

a + b = 3

Solving this system, we have a = 8 and b = - 5

So we have Area = (x + 8) * (x - 5)

So Length = x+8 and Width = x-5

Perimeter = 2*L + 2*W = 2x + 16 + 2x - 10 = 4x + 6