\(\frac{1}{2}x+\frac{3}{5}x=-\frac{2}{3}\)
\(=x\left(\frac{1}{2}+\frac{3}{5}\right)=-\frac{2}{3}\)
\(=x\cdot\frac{11}{10}=-\frac{2}{3}\)
\(\Rightarrow x=-\frac{2}{3}:\frac{11}{10}\)
\(\Rightarrow x=-\frac{20}{33}\)
x.(1/2+3/5)=-2/3
x.7/10=-2/3
x=-2/3:7/10
x=-20/20
Vậy x=-20/21