Đáp án+Giải thích các bước giải:
`a. $\frac{7}{5}$ - $\frac{5}{6}$`
`$\frac{42}{30}$ - $\frac{25}{30}$`
`$\frac{17}{30}$
`b. $\frac{15}{7}$ : $\frac{-4}{5}$ + $\frac{15}{7}$ : $\frac{5}{9}$`
`$\frac{15}{7}$ . $\frac{5}{-4}$ + $\frac{15}{7}$ . $\frac{9}{5}$`
`$\frac{15}{7}$ . ($\frac{5}{-4}$ + $\frac{9}{5}$)`
`$\frac{15}{7}$ . ($\frac{25}{-20}$ + $\frac{36}{20}$`
`$\frac{15}{7}$ . $\frac{-11}{-20}$
`$\frac{15}{7}$ . $\frac{11}{20}$
`$\frac{33}{28}$
`c,|$\frac{-4}{7}$| + ($\frac{1}{3}$ - $\frac{1}{2}$)²`
`$\frac{4}{7}$ + ($\frac{2}{6}$ - $\frac{3}{6}$)²`
`$\frac{4}{7}$ + ($\frac{2}{6}$ + $\frac{-3}{6}$)²`
`$\frac{4}{7}$ + ($\frac{-1}{6}$)²`
`$\frac{4}{7}$ + $\frac{-1}{36}$
`$\frac{144}{252}$ + $\frac{-7}{252}$`
`$\frac{137}{252}$`
