Ta có:
\(\frac{1}{2}.x+\frac{3}{5}.\left(x-2\right)=3\)
\(\Rightarrow\frac{1}{2}.x+\frac{3}{5}.x-\frac{3}{5}.2=3\)
\(\Rightarrow x.\left(\frac{1}{2}+\frac{3}{5}\right)-\frac{6}{5}=3\)
\(\Rightarrow x.\frac{11}{10}=3+\frac{6}{5}\)
\(\Rightarrow x.\frac{11}{10}=\frac{21}{5}\)
\(\Rightarrow x=\frac{21}{5}:\frac{11}{10}\)
\(\Rightarrow x=\frac{42}{11}\)
Vậy \(x=\frac{42}{11}\)
