Show me how to find the width and length please

Question

At an IMAX theater, the giant rectangular movie screen has a width 26 feet less than its length. If its perimeter is 320 feet, find the length and the width of the screen.

Answer 1

Since the width is 26 less than length, W + 26 = L

Perimeter is twice length plus twice width, so

P = 320 = 2L + 2W = 2(W+26) + 2W = 4W + 52 -> 268 = 4W -> 67 = W and 93 = L