Question

1)х 8-ых = 2 7-ых   
3)3 х(в дроби) = 7 15-ых

Answer 1

$frac{x}{8} =frac{2}{7}quad Rightarrow quad x= frac{2cdot 8}{7}= frac{16}{7}=2 frac{2}{7}\\ frac{3}{x}=frac{7}{15}quad Rightarrow quad x=frac{3cdot 15}{7}=frac{45}{7}=6 frac{3}{7}\\\P.S.; ; ; ; frac{x}{a}=frac{b}{c}quad Rightarrow quad x= frac{acdoy b}{c}; ;\\ frac{a}{x}=frac{b}{c}quad Rightarrow quad x=frac{acdot c}{b} ; .$