An open box with a square base is to be constructed from 84 square inches of material. the height of the box is 2 inches. what are the dimensions of the box? (hint: the surface area is s = x^2 + 4xh.)

Your surface area is: S=x^2+4xh=84 square inches and h=2 inches; so you get:
x^2+(4×2)x=84
x^2+8x-84=0 qhich is a quadratic equation. Using the quadratic formula you get two results for x:
x1=-14 and x2=6
choose the second (positive)