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More Lessons for Intermediate Algebra
More Lessons for Algebra
Math Worksheets

A series of free, online Intermediate Algebra Lessons or Algebra II lessons.
Examples, solutions, videos, worksheets, and activities to help Algebra students.

Solving a quadratic inequality by graphing is not difficult if you remember the basics of graphing a quadratic equation. When graphing quadratic inequalities, first graph the quadratic equation then pick a point that is not on the parabola itself and plug it into the original inequality. If the statement is true, shade in the area where that point lies. If the statement is false, shade in the other area.
How to graph quadratic inequalities on the coordinate plane?
How to graph quadratic inequalities on the coordinate plane?

Solving a Quadratic Inequality using a Sign Chart
Similar to when we solve quadratic equations, there are several ways we can solve quadratic inequalities. Solving quadratic inequalities can be done in two ways: by graphing the quadratic inequality or by using a sign chart. One of the advantages of using a sign chart to graph quadratic inequalities is that we aren't required to graph the parabola in order to solve the inequality, which saves time.
Solve a quadratic inequality using a sign chart. Find the critical values, construct a sign chart, and the use it to solve the inequality.
Example of solving a quadratic inequality by using a sign chart

Try the free Mathway calculator and problem solver below to practice various math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.  