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 ...