## Precalculus: Concepts Through Functions, A Unit Circle Approach to Trigonometry (3rd Edition)

$$x=\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}.$$
For a quadratic equation $ax^2 +bx+c=0$, the quadratic formula gives the solutions as follows $$x=\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}.$$