HELP ME PLEASE ITS MATH ALGEBRA

Question

A farmer want to build a fence along one length of a rectangular field. The field is 45 meters longer than wide.How long will the fence need to be if the perimeter is 640m

Answer 1

 

fence need to be 640m

below are dimension of field

width =w

length =l= w+45

 

perimeter = 2(l+w)

        640 = 2(w+45+w)

        640 =2(2w +45)

        640=4w +90

        550 =4w

        137.5 =w

 

       l=137.5+45=182.5 m

       w=137.5 m