3.a)[tex] \frac{x}{2} = \frac{y}{3} = \frac{z}{4}stiind~ca~z=6,vine:\\\\\\
\frac{x}{2} = \frac{6}{4}=\ \textgreater \ x= \frac{6*2}{4} =\ \textgreater \ x=12:4=\ \textgreater \ x=3\\\\\\
\frac{y}{3} = \frac{3}{2} =\ \textgreater \ x= \frac{3*3}{2} =\ \textgreater \ x=9:2=\ \textgreater \ x=4,5[/tex].
c)[tex] \frac{40}{100} *x=6\\\\
\frac{2}{5} x=6\\
x= \frac{6}{ \frac{2}{5} } \\\\
x=6* \frac{5}{2}\\\\
x=15
[/tex]