Graphing is a crude means to finding exact roots, but it can be used for estimating values. As you become proficient at graphing quadratics by hand, you may find quicker ways to estimate these values such as websites, software, or a graphing calculator.
Graphing gives a pretty strong estimate of the x-intercepts, or solutions, of a quadratic equation. Here's another way to get an estimate that may save you a little time.
Source: Khan Academy
