$\left(\left(-n^4\right)\right)^7$

$25m^2-\:49$

$\int\left(\sec\left(6x\right)-\tan\left(6x\right)\right)^2dx$

$5xy\left(4x-3y\right)$

$\int\sqrt[3]{1-3x\:}dx$

$\frac{dy}{dx}\left(xy=4\right)$

$\lim_{x\to\infty}\left(\frac{-x^2+0.3\cdot x^4}{\left(1-0.3\cdot\:x^2\right)^2+x^2}\right)$