1. If a firm is operating with constant marginal cost, it will also have constant average cost.

2. If marginal cost is increasing, average cost will also be increasing.

3. If a product requires two inputs for its production, and if the prices of the two inputs are equal, profit maximization requires that these inputs be used in equal amounts.

4. If a firm is operating at minimum short-run average cost, it is also operating at a point on its long-run average cost curve.

5. Long-run average cost can never exceed short-run average cost.

6. Long-run marginal cost can never exceed short-run marginal cost.