The dimensions of a rectangle are such that it's length is 9 in. more than its width. If the length were doubled and if the width were decreased by 4 in., the area would be increased by 110 in^2. What are the length and width of the rectangle?

Answer 1

L=9+W
Area=LW
Area+110=(2L(W-4))

so to solve for L, W substiture...

LW+110= 2(L)(W-4)
and L=9+W
(9+W)W+110=2(9+W)(W-4)

so multiply that out, you will have a quadratic in W. You can solve it with factoring, or the quadratic equation. Once you have W, calculate L