$x^9+27y^6$

$\left(\frac{x^4}{6}+\frac{8}{m^2}\right)\left(\frac{x^4}{6}-\frac{8}{m^2}\right)$

$\frac{d}{dx}x^4\cdot e^{-2x}$

$2b^{-1}\cdot b^2$

$\lim_{t\to0}\left(\left(\frac{1}{t}-\frac{1}{t^{2}+t}\right)\right)$

$2x^2\left(3x^2+x+3x^3+x^5\right)$

$\lim_{x\to\infty}\left(\frac{2x^3-3}{x^3+x}\right)$