We are doing solving polynomials using the zero factor property and here is the question:

Question

Marie has a rectangular board 18 inches by 23 inches around which she wants to put a uniform border of shells. If she has enough shells for a border whose area is 282 square inches, determine the width of the border. (the border has x's as the width and length)

Answer 1

So the board AND the border have an area of
A2=(18+x)(23+x)
The board alone is
A1=18*23
A2-A1=282
Solve for x.