Question

1.So sánh

a.\(\dfrac{21}{52}\)và\(\dfrac{-213}{523}\)

b.\(\dfrac{22}{35}\)và\(\dfrac{103}{17}\)

c.\(\dfrac{-2525}{4949}\)và\(\dfrac{-131313}{373737}\)

Answer 1

a)Vì \(\dfrac{21}{52}>0\); \(\dfrac{-213}{523}< 0\)

\(\Rightarrow\)\(\dfrac{21}{52}>\dfrac{-213}{523}\)

b)Ta có :\(\dfrac{22}{35}< 1\) ;\(\dfrac{103}{17}>1\)

\(\Rightarrow\)\(\dfrac{22}{35}< \dfrac{103}{17}\)

c)Ta có :\(\dfrac{-2525}{4949}=\dfrac{-25}{49}\) ;\(\dfrac{-131313}{373737}=\dfrac{-13}{37}\)

Lại có :\(\dfrac{25}{49}>\dfrac{25}{50}=\dfrac{1}{2}\) hay \(\dfrac{-25}{49}< \dfrac{-25}{50}=\dfrac{-1}{2}\)(1)

và \(\dfrac{13}{37}< \dfrac{13}{26}=\dfrac{1}{2}\) hay \(\dfrac{-13}{37}>\dfrac{-13}{26}=\dfrac{-1}{2}\) (2)

Từ (1) và (2) \(\Rightarrow\)\(\dfrac{-2525}{4949}< \dfrac{-131313}{373737}\)