Question

the length of a rectangle is 9 inches less than twice the width. if the perimeter of the rectangle is 84 inches, find the dimensions of the rectangle.

Answer 1

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