$\dfrac{xy+y+4}{x^{3}y-16x^{2}y+64xy}$

$\dfrac{xy+9y+12}{x^{2}y-8xy+x-8}$

$\dfrac{xy^{2}+13xy-8y}{x^{2}y-8xy}$

$\dfrac{xy^{2}+13xy-8y}{x^{3}y-16x^{2}y+64xy}$