解:3a³b²c-12a²b²c²+9ab²c³=3ab²c(a²-4ac+3c²)=3ab²c(a-c)(a-3c)
=3ab²c(a²-4ac+3c²)=3ab²c(a-c)(a-3c)
=3abC(a^2b一4abC十3bC)=