$\left(5m^3+3m^4\right)\left(5m^3-3n^4\right)$

$\left(\sqrt{14}+3\sqrt{5}\right)\left(\sqrt{14}-3\sqrt{5}\right)$

$\frac{1}{10}y-4=-15$

$9^{-2x-x^2}=9^{-8}$

$\lim_{x\to-2i}\left(\frac{2x-\left(x+2i\right)^2}{\left(x^2+4\right)^2}\right)$

$\left(9x^3+11-9x\right)-\left(6x^3-10\right)$

$\left(-9\cdot9\right)+\left(-3\right)$