A rectangular box has a square base and a height that is one more than 3 times the length of a side of the base. If the sides of the base are each increased by 2 inches and the height is increased by 3 inches the volume of the box increases by 531 cubic inches. What are the dimensions of the original box?
as before, you just need to solve
(x+2)^2 * (3x+1 + 3) = x^2(3x+1) + 531
solve for x, then finish it off