$\:x^2\:-\:x\:+\:20\left(x-5\right)$

$\frac{dy}{dx}=\frac{x^3}{y};y\left(0\right)=2$

$9n^2+n^3+18n$

$\lim_{x\to1}\left(\frac{\ln2x^2-1}{\tan\left(x-1\right)}\right)$

$y'+ty=t$

$\sec\left(x\right)+\csc\left(x\right)=\frac{1-\tan\left(x\right)}{\sin\left(x\right)}$

$x^2-16\:+\:x^2-25$