Đáp án:
`a,` ⇒ $\dfrac{-15}{56}$
`b,` ⇒ $\dfrac{61}{360}$
Giải thích các bước giải:
`a,` $\dfrac{66}{-336}$ `-` $\dfrac{25}{350}$
`=` $\dfrac{-66}{336}$ `-` $\dfrac{25}{350}$
`=` $\dfrac{-11}{56}$ `-` $\dfrac{1}{14}$
`=` $\dfrac{-11}{56}$ `-` $\dfrac{4}{56}$
`=` $\dfrac{-15}{56}$
`b,` $\dfrac{50}{-144}$ `-` $\dfrac{93}{-180}$
`=` $\dfrac{-50}{144}$ `-` $\dfrac{-93}{180}$
`=` $\dfrac{-25}{72}$ `-` $\dfrac{-31}{60}$
`=` $\dfrac{-125}{360}$ `-` $\dfrac{-186}{360}$
`=` $\dfrac{61}{360}$
