The length of a rectangle is 10 centimeters less than its width. What are the dimensions of the rectangle if its area is 200 square​ centimeters?

Question

What is the length and the width?

Answer 1

A = lw = 200

l = w - 10

(Nonsense because length is by definition greater than width, but, ok)

Substitute:

200 = (w - 10)w

200 = w^2 - 10w

w^2 - 10w - 200 = 0

I can visually factor this:

(w - 20)(w + 10) = 0

w = 20, or w = -10 (ignore this solution)

w = 20, l = 10