$\frac{54x^2y^2z^2}{-6xy^2z^5}$

$x^2+1\le4x-3$

$\lim_{x\to0}\left(\frac{2x^3-x^2}{2-x-x^4}\right)$

$2\left(x+1\right)+3\left(x+1\right)=20$

$\left(\sqrt{\infty\:^2-1}-\infty\:-1\right)$

$2x+20=-30$

$x\left[n\right]\:=\:y\left[n+2\right]-4y\left[n+1\right]+3y\left[n\right]$