Using Quadratic Formula in Systems of Nonlinear Inequalities - Expii

Sometimes in a system of nonlinear inequalities, you need to solve a quadratic inequality at some point. To do that, you can write the inequality in the form P(x) > 0 or P(x) ≥ 0, and then factor P(x) either by hand or using the quadratic formula. Then you can find the intervals where P is positive or negative.