### Practice Test

In the following exercises, simplify.

$\sqrt{81+144}$

$\sqrt{36{n}^{13}}$

$5\sqrt{20}+2\sqrt{125}$

$\left(2-5\sqrt{x}\right)\left(3+\sqrt{x}\right)$

ⓐ $\sqrt[4]{{a}^{12}}$

ⓑ $\sqrt[3]{{b}^{21}}$

$\sqrt{\frac{64{r}^{12}}{25{r}^{6}}}$

$\frac{\sqrt[5]{256{x}^{7}}}{\sqrt[5]{4{x}^{2}}}$

ⓐ ${256}^{\frac{1}{4}}$

ⓑ ${243}^{\frac{1}{5}}$

${25}^{-\frac{5}{2}}$

${\left(27{s}^{\frac{3}{5}}\right)}^{\frac{1}{3}}$

In the following exercises, rationalize the denominator.

$\frac{\sqrt{3}}{\sqrt{x}+\sqrt{5}}$

In the following exercises, solve.

$\sqrt{3u-2}=\sqrt{5u+1}$

In the following exercise, solve.

A helicopter flying at an altitude of 600 feet dropped a package to a lifeboat. Use the formula $t=\frac{\sqrt{h}}{4}$ to find how many seconds it took for the package to reach the hiker. Round your answer to the nearest tenth of a second.