$3-2\left(b-2\right)=2-7b$

$\lim_{x\to\infty}\cos\left(\frac{x}{m}\right)^m$

$9x+1+\left(-12x\right)-8$

$r^2+r-2=0$

$\frac{dy}{dx}=\frac{y\sec\left(x\right)}{ye^{y^2}}$

$\frac{d^2}{dx^2}\left(\left(\frac{x^3}{y^2}\right)+\left(\frac{y^3}{z^3}\right)\right)$

$\frac{dx}{dt}=0.6-\frac{3x\left(t\right)}{500}$