The length of a rectangle is 3n+ 2 and its width is n-1. the perimeter of the rectangle is twice the sum of its length and its width. write an expression that represents the perimeter of the rectangle. find the perimeter of the rectangle when n= 4 inches

Length, L = 3n + 2
Width, W  =  n - 1

Perimeter, P = 2*(L + W)

                   = 2*( 3n + 2 + n - 1)

                   = 2*(3n + n + 2 - 1)

                   =  2*(4n + 1)

                   = 2*4n + 2*1

                   = 8n + 2  

Perimeter = (8n + 2)

Perimeter, when n = 4,  8n + 2 = 8*4 + 2 = 32 +2 = 34

Perimeter = 34 inches.