Question

So sánh 

a)\(\dfrac{-25}{37}\) và \(\dfrac{-20}{31}\)

b)\(\dfrac{-8}{13}\) và \(\dfrac{-5}{11}\)

Answer 1

a ) \(\dfrac{-25}{37}\) và \(\dfrac{-20}{31}\)

\(\dfrac{-25}{37}\) \(=\) \(\dfrac{-25.2}{37.2}\) \(=\) \(\dfrac{-50}{74}\)                                        vậy \(\dfrac{-50}{54}\) \(>\) \(\dfrac{-40}{62}\)

\(\dfrac{-20}{31}\) \(=\) \(\dfrac{-20.2}{31.2}\) \(=\) \(\dfrac{-40}{62}\)                     

b)   \(-\dfrac{8}{13}\) và \(\dfrac{-5}{11}\) 

\(\dfrac{-8}{13}\) \(=\) \(\dfrac{-8.2}{13.2}\) \(=\) \(\dfrac{-16}{26}\)                                                vậy \(\dfrac{-16}{26}\) \(>\) \(\dfrac{-10}{22}\)

\(\dfrac{-5}{11}\) = \(\dfrac{-5.2}{11.2}\)  \(=\)  \(\dfrac{-10}{22}\)