WHAT I HAVE LEARNED A quadratic inequality is any inequality that can be expressed in any of the forms: ax2 + bx + c < 0 ax2 + bx + c > 0 ax2 + bx + c = 0 ax2 + bx + c 20 where a, b and c are real numbers and a+0. Steps in Solving a Quadratic Inequality 1.) Express the quadratic inequality as a quadratic equation in the form of ax2 + bx + c = 0 and then solve for x 2.) Locate the numbers found in step one on a number line. They serve as the boundary points. The number line will be divided into regions. 3.) Choose one number from each region as a test point. Substitute the test point to the original inequality. 4.) If the inequality holds true for the test point, then that region belongs to the solution set, otherwise, it is not part of the solution set of the inequality. 5.) Write the solution set as interval notation.​