a + b + c = 0 => a + b = -c ; b + c = -a ; a + c = -b
Do đó \(M=\frac{-c}{c}+\frac{-a}{a}+\frac{-b}{b}=-1+\left(-1\right)+\left(-1\right)=-3\)
Ta có :\(a+b+c=0=>a+b=-c;b+c=-a;a+c=-b\)
Do đó : \(M=-\frac{c}{c}+-\frac{b}{b}+-\frac{c}{c}=\left(-1\right)+\left(-1\right)+\left(-1\right)=-3\)