I understand better with supplementary graphs, please include a graph with your explanation.

The table above gives the domestic supply of, and demand for, cheese in the United States.

The world price of cheese is $12 per pound, and trade is unrestricted.

How many pounds of cheese are consumed, produced and imported in the U.S.?

Now, from the above situation of free trade, a $3 per pound tariff is imposed. a complete analysis would be much appreciated.

Quantity supplied Quantity demanded Price (thousands of (thousands of (dollars per pound) pounds per year) pounds per year) 21 120 60 18 100 100 15 80 140 12 60 180 9 40 220