The volume of a stock, or number of shares traded, is modeled over time during a given day by S (x) = x 5 - 3 x 4 + 10 x 2 - 6x + 30. The cost per share of that stock during that day is modeled by C (x) = 0.004 x 4 - 0.02 x 2 + 0.3x + 4. Write a polynomial function V (x) to model the changing value during that day of the trades made of shares of that stock.