College Algebra
posted by Alicia .
Suppose that the length of a rectangle is 3 inches longer than the width and that the perimeter of the rectangle is 78.
Set up an equation involving only L, the length of the rectangle.
Solve this equation algebraically to find the length of the rectangle. Find the width as well.
Lenght Width

Let w be the width of the rectangle.
L = w + 3
(L  3 = w)
2L + 2w = 78
2L + 2(L3) = 78
2L + 2L  6 = 78
4L = 84
L = 21 in.
W = L  3 = 21  3 = 18 in.