$\left(4\right)\left(7xy\right)$

$\frac{-y^2+2y+8}{4-y}$

$\left(\frac{10}{2}m^4\right)\left(\frac{4}{3}m\right)$

$\frac{12x^5y^4-18x^4y^6}{-6x^2y^3}$

$\left(2x^2y-2y\right)\left(\frac{dy}{dx}\right)+\left(1+2xy^2\right)=0$

$3xy^2-2xy+y,\:x=-2,\:y=2$

$\frac{-3x^2+x+57}{\left(3x-2\right)\left(x-5\right)^2}$