$\left(x^6y^{-2}z^{-4}\right)\left(-4yz^{-3}\right)\left(4xy^{-3}z^6\right)$

$3z^2+z-2$

$\int_1^2\left(\frac{x}{\left(x^2-1\right)^2}\right)dx$

$\left(\frac{3}{7}m^2n\right)\left(-\frac{7}{14}a^2m\right)$

$x^2-20x+64$

$20xy^4z^{12}4x^3yz^{24}$

$\frac{\left(12m^2+19m^4-1+3m+30m^5\right)}{\left(4m^2+5m^3-2m+1\right)}$