a( 1 b + 1 c )+b( 1 a + 1 c )+c( 1 a + 1 b )+2= a b + a c + b a + b c + c a + c b +2= a+c b + a+b c + b+c a +2∵a+b+c=0,∴a+c=-b,a+b=-c,b+c=-a,∴原式= ?b b + ?c c + ?a a +2=-1-1-1+2=-1.