Có: $\frac{51}{119}$ = $\frac{51÷17}{119÷17}$ = $\frac{3}{7}$
$\frac{189}{105}$ = $\frac{189÷21}{105÷21}$ = $\frac{9}{5}$
$\frac{84}{96}$ = $\frac{84÷12}{96÷12}$ = $\frac{7}{8}$
⇒ $\frac{7}{8}$ = $\frac{84}{96}$; $\frac{9}{5}$ = $\frac{189}{105}$; $\frac{3}{7}$ = $\frac{51}{119}$