Is each of the following statements true or false? In either case, briefly justify your answer. (a) If a firm has economies of scale, then its average cost is decreasing and lower than its marginal...

Is each of the following statements true or false? In either case, briefly justify your answer. (a) If a firm has economies of scale, then its average cost is decreasing and lower than its marginal cost. (b) A firm whose total cost function is C(Q)=Q^2+Q must have economies of scale. (c) A firm with total cost function ?(Q) = 3Q+2 must have constant returns to scale. Plz do fast asap