Răspuns:
[tex] \frac{2x}{2 \times \frac{1}{3} } = \frac{9}{5 \times \frac{1}{4} } = > \frac{x}{ \frac{1}{3} } = \frac{9}{ \frac{5}{4} } = > 3x = \frac{36}{5} = > x = \frac{12}{5} [/tex]
[tex] \frac{7x}{42} = \frac{15}{9} = > \frac{x}{6} = \frac{5}{3} = > 3x = 30 = > x = 10[/tex]