A rectangular box

A rectangular box with open top is to be formed from a rectangular piece of cardboard which is 180 inches by 84 inches by cutting a square of size x inches from each corner, and folding up the sides. What is the largest possible volume of such a box? F(x) = over the interval from ____ to ____We find that f(x) has a stationary point at x=To verify that f(x) has a maximum at this stationary point we compute the second derivative f”(x) and find that its value at the stationary point is______a negative number.Thus the maximum volume of the box is