(9a^2-6a+1)/1-3a+b-3ab=(3a-1)^2/(1+b)-3a(1+b)=(3a-1)^2/(1+b)(1-3a)=-(3a-1)/(1+b)
9a^2-6a+1 (3а+1)^2 (3а+1)(3а+1) 1
===;
1-3a+b-3ab (3аb+b)(3a+1) b(3a+1)(3a+1) b
(9a^2-6a+1)/1-3a+b-3ab=(3a-1)^2/(1+b)-3a(1+b)=(3a-1)^2/(1+b)(1-3a)=-(3a-1)/(1+b)
9a^2-6a+1 (3а+1)^2 (3а+1)(3а+1) 1
===;
1-3a+b-3ab (3аb+b)(3a+1) b(3a+1)(3a+1) b