a) $\frac{7}{5}$ - x = $\frac{3}{10}$
⇔ x = $\frac{7}{5}$ - $\frac{3}{10}$
⇔ x = $\frac{14}{10}$ - $\frac{3}{10}$
⇔ x = $\frac{11}{10}$
b) $\frac{4}{7}$ : x = $\frac{5}{15}$
⇔ x = $\frac{4}{7}$ : $\frac{5}{15}$
⇔ x = $\frac{4}{7}$ × $\frac{15}{5}$
⇔ x = $\frac{12}{7}$
- Chúc bạn học tốt !!!! ~
