Đáp án+Giải thích các bước giải:
$\dfrac{35}{28}=\dfrac{35:7}{28:7}=\dfrac{5}{4}$
$\dfrac{85}{51}=\dfrac{85:}{51:}=\dfrac{85:17}{51:17}=\dfrac{5}{3}$
$\dfrac{65}{39}=\dfrac{65:13}{39:13}=\dfrac{5}{3}$
$\dfrac{75}{100}=\dfrac{75:25}{100:25}=\dfrac{3}{4}$
$\dfrac{189}{105}=\dfrac{189:21}{105:21}=\dfrac{9}{5}$