Ответ:

[tex]\frac{2x-1}{x^{2} -6x+9}:\frac{1-2x}{x^{2} -3x}=\frac{(2x-1)*(x^{2} -3x)}{(x^{2} -6x+9)*(1-2x)}=\frac{-(1-2x)*x*(x-3)}{(x-3)^{2} *(1-2x)}=\frac{-x}{x-3}=-\frac{x}{x-3}[/tex]