How to solve these and how do we know if to increase or decrease

A firm facing a downward sloping demand curve is producing a level of output at which price is $9, marginal revenue is $7, and average total cost, which is at its minimum value, is $4. In order to maximize profit, the firm should x price. A firm with market power is producing a level of output at which price is $8, marginal revenue is $5, average variable cost is $6, and marginal cost is $10. In order to maximize profit, the firm should x price. A monopolist is producing a level of output at which price is $78, marginal revenue is $42, average total cost is $42, and marginal cost is $60. In order to maximize profit, the firm should In order to maximize profit, the firm should x output. Not answered tion The correct answer is: decrease Mark 0.00 out of 1.00