A carpenter is building a bookcase of height h, length 2h, and width w. The bookcase has two shelves. The plywood to be used for the back costs $1.50 per square foot. The top, bottom , sides, and shelves will be made of pine costing $5 per square foot. Write an equation expressing the total cost of the materials. Enter your answer in the form: C = ahb + chw, where a, b, c are integers.