Calculus Problems Optimization

A poster is to have an area of 180 inches^2 with 1 inch margins at the bottom and sides and a 2 inch margin at the top. What dimensions will give the largest printed area?

A box with an open top is to be constructed from a square piece of cardboard 3ft wide by cutting out a square from each of the four corners and bending the sides. Find the largest volume the box can have.