The equation for the perimeter of a rectangle is P = 2(l+w) P is perimeter, l = length, and w = width. Since the length is 5 less than the width, we could also say that l = w-5. Now, plug it into the equation.
86 = 2(w-5+w)
86 = 2(2w-5)
86 = 4w-10
86+10 = 4w-10+10
96 = 4w
96/4 = 4w/4
24 = w
Since the length is 5 less than the width, or 24, plug it in.
l = w-5
l = 24-5
l = 19
