$\frac{1}{2}$ .x+$\frac{3}{5}$ .(x-2)=3
$\frac{1}{2}$ .x+$\frac{3}{5}$ .x-$\frac{6}{5}$ =3
x.($\frac{1}{2}$+$\frac{3}{5}$ )-$\frac{6}{5}$=3
x.$\frac{11}{10}$ -$\frac{6}{5}$=3
x.$\frac{11}{10}$ =3+$\frac{6}{5}$
x.$\frac{11}{10}$ =$\frac{21}{5}$
x=$\frac{21}{5}$:$\frac{11}{10}$
x=$\frac{42}{11}$
Vậy x=$\frac{42}{11}$