Question

Quick!!

Shandra has a sheet of cardboard whose area is x2 + 2x - 15 square inches. We know that the length of the cardboard
sheet is (x + 5) inches. What is its width? (Hint: area = length width)

Answer 1

(x - 3) inches

Explanation:

the ratio of -15 (of the area term) and +5 (of the length term) suggests a term for the width ending in -3. and we need an x in there to get x² for the area.

so, immediate assumption is (x-3) for the width.

let's check

(x+5)(x-3) = x² + 5x - 3x - 15 = x² + 2x - 15

correct.