## Elementary Algebra

$\approx-32.4$
Using the properties of radicals, a rational approximation (to the nearest tenth) of the given expression, $14\sqrt{13}-17\sqrt{13}+3\sqrt{13}-4\sqrt{13}-5\sqrt{13} ,$ is \begin{array}{l}\require{cancel} (14-17+3-4-5)\sqrt{13} \\\\= -9\sqrt{13} \\\\ \approx-32.4 .\end{array}