Posted by Lyle Eleda on .
You are creating a metal border of uniform width for a wall mirror that is 20 inches by 24 inches. You have 416 square inches of metal to use. Write and solve an equation to find the border's width.

Algebra 2 
Steve,
final dimensions of the framed mirror:
(20+2w) x (24+2w)
final area: (20+2w)(24+2w)
mirror area: 20*24
border area: (20+2w)(24+2w)480
= 480 + 88w + 4w^2  480 = 416
w^2 + 22w  104 = 0
(w+26)(w4) = 0
w = 4