W = L - 2
Perimeter = 2 ( W + L) = 68 ....so.......
68 = 2 ( L - 2 + L) simplify
68 = 2 ( 2L - 2) divide both sides by 2
34 = 2L - 2 add 2 to both sides
36 = 2L divide both sides by 2
18 = L .... so W = L - 2 = 18 - 2 = 16
Area = L x W = 18 x 16 = 288 sq units
