Find all values of $\displaystyle {x}$ for which the rational expression is undefined.

$\displaystyle \frac{{{x}+{7}}}{{{\left({x}-{3}\right)}{\left({x}-{10}\right)}}}$

The expression is undefined when $\displaystyle {x}=$

If there is more than one answer, write it as a list, using commas to separate your answers.