Câu trả lời:

\(=\left(\dfrac{10}{6}-\dfrac{3}{6}\right)\div\left(\dfrac{6}{12}-\dfrac{20}{12}\right)=\dfrac{7}{6}\div\dfrac{-14}{12}=\dfrac{84}{72}\div\dfrac{-84}{72}=\dfrac{-1}{72}\)