$\lim_{x\to12}\left(\frac{x-12}{\sqrt{x}-\sqrt{12}}\right)$

$\left(\frac{1}{3}p-\frac{4}{7}q\right)\left(\frac{1}{9}p^2+\frac{4}{21}pq+\frac{16}{41}q^2\right)$

$\left(x^3-3x^2y\right)\frac{dy}{dx}$

$\left(5v+3\right)-\left(4w+5v-7\right)+\left(6w-20\right)$

$\lim_{x\to5}\left(\frac{sin\left(x-5\right)}{\left(x-5\right)^5}\right)$

$\sec\left(x\right)-\frac{2\sqrt{3}}{3}=0$

$\lim_{x\to4}\left(\frac{-5x^2+20x}{x^3-3x^2-4}\right)$