a. \(\dfrac{-18}{91}\) và \(\dfrac{-23}{114}\)

\(\dfrac{18}{91}< \dfrac{18}{90}=\dfrac{1}{5}=\dfrac{23}{115}< \dfrac{23}{114}\)

\(\Rightarrow\dfrac{-18}{91}>\dfrac{-23}{114}\)

b. \(\dfrac{-22}{35}\) và \(\dfrac{-103}{177}\)

\(\dfrac{22}{35}=\dfrac{110}{175}>\dfrac{103}{175}>\dfrac{103}{177}\)

\(\Rightarrow\dfrac{-22}{35}< \dfrac{-103}{177}\)

a: \(\dfrac{-18}{91}>\dfrac{-18}{90}=\dfrac{-1}{5}\)

\(\dfrac{-23}{114}< \dfrac{-23}{115}=\dfrac{-1}{5}\)

Do đó: \(\dfrac{-18}{91}>\dfrac{-23}{114}\)

b: \(\dfrac{-22}{35}=\dfrac{-3894}{6195}\)

\(\dfrac{-103}{177}=\dfrac{-103\cdot35}{177\cdot35}=\dfrac{-3605}{6195}\)

mà -3894<-3605

nên -22/35<-103/177

a: \(\dfrac{119}{117}=1+\dfrac{2}{117}\)

\(\dfrac{117}{115}=1+\dfrac{2}{115}\)

mà 2/117<2/115

nên \(\dfrac{119}{117}< \dfrac{117}{115}\)

hay \(-\dfrac{119}{117}>-\dfrac{117}{115}\)

b: \(\dfrac{-22}{35}=\dfrac{-22\cdot177}{35\cdot177}=-\dfrac{3894}{6195}\)

\(\dfrac{-103}{177}=\dfrac{-103\cdot35}{177\cdot35}=\dfrac{-3605}{6195}\)

mà -3894<-3605

nên -22/35<-103/177

a)  ( -18/91) < (-18/90)=-1/5

-23/114 > -23/115= -1/5

Vậy -18/91 < -23/114

\(a,\dfrac{-15}{17}=-1+\dfrac{2}{17}\\ -\dfrac{19}{21}=-1+\dfrac{2}{21}\\ Vì:\dfrac{2}{17}>\dfrac{2}{21}\Rightarrow-1+\dfrac{2}{17}>-1+\dfrac{2}{21}\Rightarrow-\dfrac{15}{17}>-\dfrac{19}{21}\\ b,-\dfrac{24}{35}=-1+\dfrac{11}{35};-\dfrac{19}{30}=-1+\dfrac{11}{30}\\ Vì:\dfrac{11}{35}< \dfrac{11}{30}\Rightarrow-1+\dfrac{11}{35}< -1+\dfrac{11}{30}\\ \Rightarrow-\dfrac{24}{35}< -\dfrac{19}{30}\)

a) Ta có \(\dfrac{23}{27}>\dfrac{23}{29};\dfrac{23}{29}>\dfrac{22}{29}\)

Vậy \(\dfrac{23}{27}>\dfrac{22}{29}\)

b) Ta có \(\dfrac{15}{25}=1-\dfrac{2}{5}\)

\(\dfrac{25}{49}=1-\dfrac{24}{49}\)

Vì \(\dfrac{2}{5}=\dfrac{24}{60}< \dfrac{24}{49}\)

Vậy \(\dfrac{15}{25}>\dfrac{25}{49}\)

23/27 lớn hơn 22/29

15/25 lớn hơn 25/49

\(\dfrac{-22}{45}=-\dfrac{2266}{45.103}>-\dfrac{2295}{45.103}=-\dfrac{51}{103}\)

Ta có: \(\dfrac{-22}{45}=\dfrac{-22\cdot103}{45\cdot103}=\dfrac{-2266}{4635}\)

\(\dfrac{-51}{103}=\dfrac{-51\cdot45}{103\cdot45}=\dfrac{-2295}{4635}\)

mà -2266>-2295

nên \(\dfrac{-22}{45}>\dfrac{-51}{103}\)

Đồng tiên bạn quy đồng, rồi so sánh nhé