$21mn\:-\:12mn\:-\:3mn\:-\:8mn$

$\frac{dy}{dx}=yxe^{-x}$

$\int x^3\left(x^3-1\right)^4.dx$

$\left(5-z\right)^3$

$\sin x+\left(\cos\left(x\right)\sin\left(x\right)\right)=\sin x\left(1+\cos\left(x\right)\right)$

$\int_{\frac{1}{2}}^{\infty}\left(\frac{ln\left(2x\right)}{x^2}\right)dx$

$\frac{d}{dx}\left(3y^2-x^2=9\right)$