$\frac{12x^3+15x^2-6x}{3}$

$\left(9a^4-8b^6\right)^2$

$\frac{2x^3-6x^2+x-1}{2x^2+1}$

$\tan\left(240\right)+\cot\left(240\right)$

$\left(1+\left(\frac{1}{n}\right)\right)^{\left(\left(n+1\right)^2\right)}x^n$

$\left(-6m^3-2m^2+5\right)-\left(3m^2+8m^2-2\right)$

$\lim_{z\to i}\left(\frac{z^2-2iz-1}{z^4+2z^2+1}\right)$