[tex]16)\ \sqrt{32k}=\sqrt{16\cdot2k}=\sqrt{16}\cdot\sqrt{2k}=4\sqrt{2k}\\\\18)\ \sqrt{216x^4}=\sqrt{36\cdot (x^2)^2\cdot6}=\sqrt{36}\cdot\sqrt{(x^2)^2}\cdot\sqrt6=6x^2\sqrt6\\\\20)\ \sqrt{8m^2n^2}=\sqrt{4\cdot m^2\cdot n^2\cdot2}=\sqrt4\cdot\sqrt{m^2}\cdot\sqrt{n^2}\cdot\sqrt2=2mn\sqrt2[/tex]
[tex]22)\ \sqrt{144x^3y^3z^3}=\sqrt{144\cdot x^2\cdot y^2\cdot z^2\cdot xyz}=12xyz\sqrt{xyz}\\\\24)\ -3\sqrt3+3\sqrt5+3\sqrt5=-3\sqrt3+8\sqrt5[/tex]
