Uniform Width Border Area Problem (Quadratic Parabolas)

A 10-m by 7-m pond has a flower bed of uniform width surrounding it. If the total area is 180 square meters, what is the width of the border? Original Area is 10 by 7 But new area, with the border is (10+2x)(7+2x). So we need to solve the quadratic equation (10+2x)(7+2x)=180. This ends up being factorable !