Resposta:
a)2/3=x9
[tex] \frac{2}{3} = \frac{x}{9} \\ \\ 3x = 18 \\ \\ x = \frac{18}{3} \\ \\ x = 6[/tex]
b)3/x=6/10
[tex] \frac{3}{x} = \frac{6}{10} \\ \\ 6x = 30 \\ \\ x = \frac{30}{6} \\ \\ x = 5[/tex]
c)9/x=12/8
[tex] \frac{9}{x} = \frac{12}{8} \\ \\ 12x = 72 \\ \\ x = \frac{72}{12} \\ \\ x = 6[/tex]
