translate each statement into mathematical language
length is nine inches less than twice width. L = 2W - 9
perimeter is 84 inches 2L +2W = 84
Substitute the expression for L (2W-9) for L in the second equation resulting in the follwing
2(2W-9) + 2W = 84
4W - 18 + 2W = 84
(4W+2W) = 84+18
6W = 102
W = 102/6 = 51/3
L = 2(51/3) - 9
= L= 17-9
L=6