$3x^2-12x$

$csc\left(\theta\:\right)\left(cos\left(\theta\:\right)sec\left(\theta\:\right)-\frac{cos\left(\theta\:\right)}{sec\left(\theta\:\right)}\right)$

$\lim_{x\to0}\:\ln\left(\frac{x^3+2}{2}\right)^{\frac{1}{x}}$

$\frac{d^2}{dx^2}\left(x\ln\left(1-2x\right)\right)$

$x^2\:-\:x\:-\:7\:=\:0$

$\left(15a+3b\right)-\left(13b-2a\right)$

$\frac{dy}{dx}\left(ytanx=5x^2+4y^2\right)$