Упростить выражение б

Решите задачу:

$\frac{18xy+6-12x-9y}{9 x^{2} -36x+36}: \frac{9y^2-12y+4}{9xy-18y-6x+12}= \frac{(18xy-9y)-(12x-6)}{9 (x^{2} -4x+4)}: \frac{(3y)^2-2*3y*2+2^2}{(9xy-18y)-(6x-12)}$ $=\frac{9y(2x-1)-6(2x-1)}{9 (x-2)^2}: \frac{(3y-2)^2}{9y(x-2)-6(x-2)}=\frac{(2x-1)(9y-6)}{9 (x-2)^2}: \frac{(3y-2)^2}{(x-2)(9y-6)}=$ $\frac{3(2x-1)(3y-2)}{9 (x-2)^2}* \frac{3(x-2)(3y-2)}{(3y-2)^2}}=\frac{9(2x-1)(3y-2)^2(x-2)}{9 (x-2)^2(3y-2)^2}= \frac{2x-1}{x-2}$