# In this Section:

In this section, we review the basic definition of a quadratic equation. A quadratic equation is of the form: ax

^{2}+ bx + c = 0, where a ≠ 0. Up to this point, we have only seen how to solve a quadratic equation when it is factorable. Here, we will begin to show how to solve any quadratic equation, whether it is factorable or not. We begin by learning about the square root property. This property tells us: if k > 0, and x^{2}= k, then x = sqrt{k} or x = -sqrt{k}. For example, if we have x^{2}= 9, this means x can be 3 or -3.