The area of a rectangular computer screen is 4x^2+20x+16. The width of the screen is 2x+8. What is the length of the screen?

So the area of a rectangle is Length x Width.

A = (L) (W)

Substitute the information given:

4x^2 + 20x + 16 = (L) (2x+8)

Isolate L by dividing 2x+8:

(4x^2 + 20x + 16) / (2x + 8) = L

If you divide:

L = 2x + 2.