Question

The length of a rectangle is the sum of the width and 1. The area of the rectangle is 72 units. What is the length in units of the rectangle

Answer 1

L = 9

Explanation:

Translating this into symbols, we get L = W + 1 and A = 72 = W * L.

Substituting W + 1 for L in the latter equation, we get:

72 = W(W + 1), or:

W^2 + 1W - 72 = 0

This factors into (W + 9)(W - 8) = 0, so that W must be either -9 or +8.

Since W represents width, a physical measurement, we eliminate the negative result and conclude that W = 8 units. Then L = W + 1 = 9 units.

Note that (8)(9) = 72, as we already know.