$x^2+21x-232\:\:\:x=3$

$\log\left(\frac{x^6y^{10}}{z^{12}}\right)$

$375\cdot3$

$\lim_{t\to0}\frac{e^t+e^{-t}}{t^2}$

$\left(3xy+4z\right)^2$

$\lim_{x\to0}\left(\frac{x^2-42x+441}{sin^2\left(\pi x\right)}\right)$

$-\frac{x^2\left(2tan^2\left(2x\right)+2\right)}{tan\left(2x\right)}$