1)

[tex]\frac{y}{x^2-xy}=\frac{y}{x(x-y)}=\frac{y(x+y)}{x(x-y)(x+y)}=\frac{xy+y^2}{x(x-y)(x+y)}\\\\\frac{5}{x^2-y^2}=\frac{5x}{x(x-y)(x+y)}[/tex]

2)

[tex]\frac{4}{x-2}=\frac{4(x+3)}{(x-2)(x+3)}=\frac{4x+12}{(x-2)(x+3)}\\\\\frac{3y}{x+3}=\frac{3y(x-2)}{(x-2)(x+3)}=\frac{3xy-6y}{(x-2)(x+3)}[/tex]