Solving Quadratic Inequalities

Each of the problems below is a link. If you click on the problem, it will take you to a YouTube video of a full, step-by-step solution for the problem. You may try these problems as practice and use the videos to check your answer, or you can just watch the videos to see more worked-out example problems.

Solve the inequality x squared + 2x minus 8 is less than 0. Graph the solution and express it in interval notation.
Solve the inequality x squared + 4x + 3 is greater than 0. Graph the solution and express it in interval notation.
Solve the inequality x to the fourth minus 6x cubed + 8x squared is greater than or equal to 0. Graph the solution and express it in interval notation.