pls explain. thank you

Suppose a firm has the following total cost function: TC =75 + 3Q2, while its marginal cost function is: MC = 6Q. At what range of prices will the firm produce a positive output, or below what price will the firm shut down in the short run? Show all the steps of your work (e.g., step 1; step 2 etc.) and draw a diagram to illustrate your thinking