Determine the critical values of f(x) = ax² + bx + c.
A critical value can occur where f'(x) = 0 and also where f'(x) does not exist. Since f'(x) is a polynomial, there are no x-values where f '(x) does not exist. Therefore, the only critical values will be where f'(x) = 0.
Solve the equation f'(x) = 0 for x.