(1 point) Find the relative extrema of the function f(x) = x - 21x + 7. Specifically: 1. The relative maxima of f occur at x = 2. The relative minima of f occur at x = 3. The value of f at its relative maximum is 4. The value of f at its relative minimum is Notes: Your answer should be either a value, a comma separated list of values, or the word "none"