The revenue from selling x shirts is r(x) = 15x. the cost of buying x shirts is c(x) = 7x + 20. the profit from selling x shirts is p(x) = r(x) – c(x). what is p(x)? a. p(x) = 22x – 20 b. p(x) = 22x + 20 c. p(x) = 8x – 20 d. p(x) = 8x + 20