A company expects that the number N(x) of a product sold during a week is related to the amount spent on advertising by the function N(x) = - 5x3 +195x2 + 405x + 19,000, where x (with 0 sx $ 27) is the amount spent on advertising in thousands of dollars What is the point of diminishing returns? The point of diminishing returns is (Simplify your answer. Type an ordered pair. Do not use commas in the individual coordinates )