[tex]1)~ \frac{20}{100} *1400=280~lei\\\\
2)~18=3^2*2\\
27=3^3\\
cmmmc=3^3*2\\
cmmmc=54\\\\
3)~2x-5y=0\\
2x=5y=\ \textgreater \ x= \frac{5y}{2} \\
=\ \textgreater \ \frac{x}{y} = \frac{ \frac{5y}{2} }{y} \\
=\ \textgreater \ \frac{x}{y} = \frac{5y}{2} * \frac{1}{y} \\
=\ \textgreater \ \frac{x}{y} = \frac{5}{2} [/tex]
