Answer
$x=5$ or $x=-2$
Work Step by Step
$ x^{2}-3x-10=0\qquad$... use the Quadractic formula. $a=1,\ b=-3,\ c=-10$
$ x=\displaystyle \frac{-b\pm\sqrt{b^{2}-4ac}}{2a}\qquad$... substitute $b$ for $-3,\ a$ for $1$ and $c$ for $-10$.
$ x=\displaystyle \frac{-(-3)\pm\sqrt{(-3)^{2}-4\cdot(-10)\cdot 1}}{2\cdot 1}\qquad$... simplify.
$x=\displaystyle \frac{3\pm\sqrt{9+40}}{2}$
$x=\displaystyle \frac{3\pm\sqrt{49}}{2}$
$ x=\displaystyle \frac{3\pm 7}{2}\qquad$... the symbol $\pm$ indicates two solutions.
$x=\displaystyle \frac{3+7}{2}$ or $x=\displaystyle \frac{3-7}{2}$
$x=5$ or $x=-2$
