$\int\frac{e^2}{\left(1-e^u\right)^2}\:du$

$\left(\sec^2\left(u\right)-1\right)\left(\csc^2\left(u\right)-1\right)$

$3x^{2}-2\cdot\left(x-3\right)\cdot\left(x+3\right)$

$\left(7x^6-4b^4\right)^2$

$x^3-4x^2-19x+6$

$\frac { \sqrt { 4 } } { n }$

$25\:+\:13\:-\left(9-4\:\right)\left[-45\:+\:\left(12\:+\:34\:\right)\:-8\right]$