Constant Marginal Cost. Consider a firm operating in the long run with an indivisible input that has a cost of $120. The marginal cost of production is constant at $3 per unit. Use the three-point curved line drawing tool to draw and label the firm's long-run average-cost curve for 5 to 10 units of output. Note: if you are not prompted for a label, you have used the wrong drawing tool The long-run average cost drops from $for the first unit to $for the tenth unit. (Enter your responses rounded to the nearest penny.)