$\lim_{x\to0}\left(1-9x\right)^{\frac{1}{x}}$

$44x-4^{4}+9$

$2\int x^3\sqrt{1-x^2}dx$

$6a^2b-8a^3b^2+10a^4b^3$

$\left(\frac{2}{3}m^2+\frac{1}{5}n\right)\left(\frac{2}{3}m^2-\frac{1}{5}n\right)$

$\left(2m^3+y^3\right)\left(4m^6-2m^3y^3+y^6\right)$

$\left(-15a^nb^3\right)\cdot\frac{4}{5}ab$