ta có x.1=21(vì 2017:2017=1 nên triệt tiêu)
x =21:1=21
\(\frac{2017}{2017\cdot\left(x\cdot1\right)}=21\)
\(\Leftrightarrow\frac{1}{x}=21\)
\(\Leftrightarrow x=\frac{1}{21}\)
\(\frac{2017}{2017.\left(x.1\right)}=21\)
\(\frac{1}{x}=21\)
\(x=\frac{1}{21}\)
ta có ';
2017:2017.(X.1)=21
1.(X.1)=21
X.1=21
X=21