Do you agree or disagree with the following statement when marginal revenue equals marginal cost total cost equals total revenue and the firm makes zero profit?

Answer 1

No it is not true.

MC=MR it's "only" the condition of optimization of the firm.

This is the condition under which the firm chooses the best quantity to produce given its cost structure. Under this condition you are sure that given that structure the firm maximizes its profits. But this does not implies that the firm is actually making profits(f.e. it could miximize its profits simply making a loss of -21 instead of -22). To be sure of that you have to consider the total cost function. The total cost function is defined as:

TC=qxVC+FC

than you have to consider the revenue function

TR=qxP

to see if the firm it's actually making profits you have to calculate

TR-TC=Profit

note that you can't find the total cost function by the marginal cost function.

q=quantity

VC=variable cost

FC=fixed costs

P=price of item sold