Answer : The length is 26ft
First, you would have to set an equation to find the value of x. To find this equation you would multiply both expressions for length and width by two. You would get the expression (6x-8) for length and the expression (2x) for width. You would then add these and make them equal to the perimeter, 72. You would get the equation 8x-8=72. Solving this equation would give you x=10. You just plug this value of x into the expression for length, which gives you the answer 26 ft.