\(\frac{ab}{b}=a.\frac{b}{b}=a.1=a\)
\(\frac{bc}{c}=b.\frac{c}{c}=b.1=b\)
\(\frac{ca}{a}=c.\frac{a}{a}=c.1=c\)
Mà vì: \(\frac{ab}{a}=\frac{bc}{c}=\frac{ca}{a}\)
\(\Rightarrow a=b=c\)
\(\frac{ab}{b}=\frac{bc}{c}=\frac{ca}{a}=ab\div b=bc\div c=ca\div a\)
\(\Rightarrow a=b=c\)
Từ \(\frac{ab}{b}=\frac{bc}{c}=\frac{ca}{a}\Rightarrow a=b=c\)
Zậy đpcm.
đề
\(\Rightarrow\)\(\frac{abc}{bc}\)= \(\frac{abc}{ac}\)=\(\frac{abc}{ab}\)
\(\Rightarrow\)a=b=c