The length of the flat screen tv is 5 inches less than 3 times it's width. if the perimeter of the tv is 150 inches, find the dimensions

AS we don't know the width so  let consider width=x inches

According to given condition

 length = (3x -5) inches

TV screen is rectangular shaped so

Perimeter= 2( length +width) =2{(3x-5)+ (x)}              equation 1

also given   Perimeter = 150 inches     equation 2

comparing equation 1 &2  

2{(3x-5)+ (x)} =150

2{3x-5+x} =150

2{4x-5} =150

8x-10 =150

Adding 10  both sides

8x -10 +10 =150+10

8x=160

dividing 8 both sides

8x/8= 160/ 8

x= 20 inches    width of screen.

length =( 3x-5) ={3(20) -5}

                       =60-5

             length   =55