Please help! The graph shows the amounts customers pay for
x pounds of cheese at a deli counter. Customers
pay a certain price per pound up to exactly 5 pounds. If a customer buys more than 5 pounds, then the price per pound for the entire purchase is discounted.

Complete the following:

A piecewise-defined function for the graph is

f(x)=
___,0 ___

Customers who buy up to 5 pounds pay $___ per pound. Customers who buy more than 5 pounds pay $20 for the first 5 pounds. They pay $___ per pound for each pound over 5 pounds.