24/45<48/49. ta lập tỉ số không gian

Ta có: \(\frac{24}{25}\frac{x}{x}\frac{2}{2}=\frac{48}{50}\)
Vì 50>49 nên \(\frac{24}{50}

câu 1 : quy đồng 2 ps ta đc : \(\frac{621}{756},\frac{672}{756}\) mà \(\frac{621}{756}

-25/20 < 20/25

15/21 > 21/49

-19/49 > -23/47

ta có :\(\frac{12}{25}\frac{1}{2}\left(2\right)\)

Từ ( 1 ) và ( 2 ) \(\Rightarrow\frac{12}{25}

1\2 o dau

thì lấy 1/2 ra để so sánh chí bạn ko biết à

Ta co

\(\frac{12}{25}\frac{12}{25}\Rightarrow\frac{25}{49}>\frac{12}{25}\)

Ta có:25.25>12.49

=>\(\frac{25.25}{25.49}>\frac{12.49}{25.49}\Rightarrow\frac{25}{49}>\frac{12}{25}\)

Ta có :

\(\frac{15}{25}=\frac{15\times49}{25\times49}=\frac{735}{1225};\frac{25}{49}=\frac{25\times25}{49\times25}=\frac{625}{1225}\)

Vì 735 > 625 nên \(\frac{15}{25}>\frac{25}{49}\)

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

12/25>25/49

Ta có : 

\(\frac{12}{25}< \frac{12}{29}\)

             \(\frac{12}{29}< \frac{25}{29}\)

=> \(\frac{12}{25}< \frac{12}{29}< \frac{25}{29}\)

Vậy \(\frac{12}{25}< \frac{25}{29}\)

\(\frac{12}{25}< \frac{25}{49}\)