$2x^2-5x-12$

$\frac{-5mn}{mn}$

$\csc\left(x\right)+1\cdot\csc\left(x\right)-1=\cot\left(x\right)\cot\left(x\right)$

$\left(2z-3\right)^2$

$\left(5x^3+1\right)^2$

$\left(4a^3-50ab^2-6a^2b^3\right)entr\left(-2\right)$

$\lim_{x\to0}\left(\frac{sin^2\left(x\right)}{2-2cos\left(x\right)}\right)$