$-9x+8-7x^2-6x^2-x+6$

$\frac{z}{6}+4=\frac{2z}{9}+3$

$\frac{\left(x^3+8\right)}{\left(x^2+\:2\right)}$

$\ln\left(x\right)+\ln\left(x-7\right)-\ln\left(60\right)$

$\lim_{x\to0}\left(\frac{x^2\cdot x\sin\left(x\right)}{\cos\left(x\right)-1}\right)$

$\frac{x^{19}-1}{x-1},t_{10}$

$\frac{dy}{dx}=-6xy\:$