=18(c-1/6)(c+1/3)/(6(1/6-c)+6y(1/6-c))=
=18(c-1/6)(c+1/3)/6(1+y)(1/6-c)=
= - 3(c+1/3)/(1+y)
при с = -6, у = 5\12:
-3(-6+1/3)/(1+5/12)=
=-3*(-17/3)/(17/12)=
=-3*(-4)=
=12
ответ:12.
