Svp help exercice 8 merci d'avance

Salut!

Ex 8:

[tex] \frac{3}{5} = \frac{9}{15} [/tex]

[tex] \frac{1}{10} = \frac{100}{1000} [/tex]

[tex] \frac{7}{2} = \frac{21}{6} [/tex]

[tex] \frac{1}{5} = \frac{100}{500} [/tex]

[tex] \frac{-3}{-7} = \frac{9}{21} [/tex]

[tex] \frac{-25}{8} = \frac{-50}{16} [/tex]

Bonne continuation =)