$12m^2n+24m^3n^2-36m^4n^3+48x^2y^3$

$\left(18\:\cdot2000\right)\:+\:\left(24\:\cdot2125\right)$

$2\cot\left(x\right)^2+5\cot\left(x\right)-3=0$

$\frac{2^6}{2^3}$

$-\left(6a-3b\right)-\left\{5a-9b-\left(2c-9b\right)\right\}$

$\lim_{x\to1}\left(\frac{1}{1-x}-\frac{1}{lnx}\right)$

$900-1z^2$