$-\left(-3\right)^{6}:\left(-3\right)^{4}$

$\left(a\:+\:\sqrt{3}\right)\left(\sqrt{3}\:-\:a\right)$

$\frac{\left(42a^2b^4-6a^3b^3+18a^3b^2\right)}{\left(6a^2b^2\right)}$

$-\frac{24}{6}+\left(\frac{3}{-3}\right)$

$\left(q-2\right)^2+4\left(q-2\right)+4$

$\left(\left(\frac{1}{3}\right)^{-2}\right)^2$

$\frac{1}{\sqrt{x-2}}$