Suppose f (x) = x³ − 7x² − 5x + 35. From calculus, the derivative of f is given by f (x) = 3x² − 14x − 5. The function f is increasing where f (x) > 0 and decreasing where f (x) < 0. The numbers at the endpoints must be tested separately to determine if they should be included in the interval describing where a function is increasing and decreasing. Because polynomials are continuous over its domain, all endpoints are included in the interval describing increasing/decreasing. Determine where f is increasing and where f is decreasing.