$\lim_{x\to2}\left(-\frac{x^2-4}{x+2}\right)$

$4x^244x+121$

$30x^2y^3-10xy^2+20xy$

$\left(ax+3by\right)^5$

$\frac{dy}{dx}=\frac{\left(e^{-y}\right)}{x^{2\:}}$

$\lim_{x\to0}\left(\frac{\cos\left(x\right)+x^2-ln\left(e+x\right)}{ex}\right)$

$\left(-1\right)^3x\left(-1\right)^4$