3x=2/5 *9
3x=18/5
x=18/5 :3
x=6/5
\(\frac{3x}{9}=\frac{2}{5}\Rightarrow5.3x=2.9\)
\(\Rightarrow15x=18\)
\(\Rightarrow x=18:15=\frac{6}{5}\)
\(\frac{3.x}{9}=\frac{2}{5}\)
\(\frac{3.x.5}{9.5}=\frac{2.9}{5.9}\)
\(\frac{15.x}{45}=\frac{18}{45}\)
\(\Rightarrow15.x=18\)
\(\Rightarrow x=18:15\)
\(\Rightarrow x=1,2\)
k nha