Algebra II Workbook For Dummies, 2nd Edition

Chapter 2

Handling Quadratic (and Quadratic-Like) Equations and Inequalities

In This Chapter

Finding solutions with radicals

Solving quadratic equations using factoring and the quadratic formula

Completing the square

Changing equations with higher powers to quadratic form

Dealing with quadratic inequalities using number lines

Quadratic equations and inequalities include variables that have powers, or exponents, of 2. The power 2 opens up the possibilities for more solutions than do linear equations (whose variables have powers of 1 — see Chapter 1). For instance, the linear equation 2x + 3 = 5 has one solution, x = 1, but the quadratic equation 2x² + 3 = 5 has two solutions, x = 1 and x = –1. You can solve quadratic equations through factoring, employing the quadratic formula, completing the square, or using the nifty square root rule when possible. Quadratic inequalities, on the other hand, are best solved by looking at intervals on a number line.

Some of the equations in this chapter ...