# How do you solve x^2- 7x + 12 = 0 using the quadratic formula?

May 2, 2018

$x = 4$ or $3$

#### Explanation:

According to quadratic formula if $a {x}^{2} + b x + c = 0$, then $x = \frac{- b \pm \sqrt{{b}^{2} - 4 a c}}{2 a}$

Here we have ${x}^{2} - 7 x + 12 = 0$ i.e. $a = 1$, $b = - 7$ and $c = 12$

and $x = \frac{- \left(- 7\right) \pm \sqrt{{\left(- 7\right)}^{2} - 4 \cdot 1 \cdot 12}}{2 \cdot 1}$

= $\frac{7 \pm \sqrt{49 - 48}}{2}$

= $\frac{7 \pm \sqrt{1}}{2}$

= $\frac{7 \pm 1}{2}$

i.e. $x = 4$ or $3$