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a/ \(\dfrac{7}{10}=\dfrac{7.15}{10.15}=\dfrac{105}{150}\)
\(\dfrac{11}{15}=\dfrac{11.10}{15.10}=\dfrac{110}{150}\)
-Vì \(\dfrac{105}{150}< \dfrac{110}{150}\)(105<110)nên \(\dfrac{7}{10}< \dfrac{11}{15}\)
b/ \(\dfrac{-1}{8}=\dfrac{-1.3}{8.3}=\dfrac{-3}{24}\)
-Vì \(\dfrac{-3}{24}>\dfrac{-5}{24}\left(-3>-5\right)\)nên\(\dfrac{-1}{8}>\dfrac{-5}{24}\)
c/\(\dfrac{25}{100}=\dfrac{25:25}{100:25}=\dfrac{1}{4}\)
\(\dfrac{10}{40}=\dfrac{10:10}{40:10}=\dfrac{1}{4}\)
-Vì \(\dfrac{1}{4}=\dfrac{1}{4}\)nên\(\dfrac{25}{100}=\dfrac{10}{40}\)
a/ \(\dfrac{7}{10}< \dfrac{11}{15}\)
c/ \(\dfrac{25}{100}=\dfrac{10}{40}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
D vì \(\dfrac{-4}{10}\)rút gọn cho 2 được\(\dfrac{-2}{5}\)
B Vì (-2).15 = (-6).5 nên \(\dfrac{-2}{5}\) = \(\dfrac{-6}{15}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
Hai phân số bằng nhau là \(\dfrac{15}{-10}\) và \(-\dfrac{3}{2}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a: \(\dfrac{5}{24}< \dfrac{15}{24}=\dfrac{5}{8}\)
b: \(\dfrac{6+9}{6\cdot9}=\dfrac{15}{54}\)
4/9=24/54
2/3=36/54
Do đó: \(\dfrac{15}{54}< \dfrac{24}{54}< \dfrac{36}{54}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(A=\frac{10^5-1+5}{10^5-1}=1+\frac{5}{10^5-1}\)
\(B=\frac{10^5-2+5}{10^5-2}=1+\frac{5}{10^5-2}\)
Nhận xét: 105 - 1 > 105 - 2 nên \(\frac{1}{10^5-1}
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\dfrac{1}{10}A=\dfrac{10^{2023}+5}{10^{2023}+50}=1-\dfrac{45}{10^{2023}+50}\)
\(\dfrac{1}{10}B=\dfrac{10^{2022}+5}{10^{2022}+50}=1-\dfrac{45}{10^{2022}+50}\)
10^2023+50>10^2022+50
=>-45/10^2023+50<-45/10^2020+50
=>1/10A<1/10B
=>A<B
Cách 1 :
Ta có :
\(A=\dfrac{10^5+4}{10^5-1}=\dfrac{10^5-1+4+1}{10^5-1}=\dfrac{10^5-1+5}{10^5-1}=1+\dfrac{5}{10^5-1}\)
\(B=\dfrac{10^5+3}{10^5-2}=\dfrac{10^5-2+3+2}{10^5-2}=\dfrac{10^5-2+5}{10^5-2}=1+\dfrac{5}{10^5-2}\)
Vì \(1+\dfrac{5}{10^5-1}< 1+\dfrac{5}{10^5-2}\Rightarrow A< B\)
Cách 2 chưa nghĩ ra!!
~ Học tốt ~
C2: Dễ thấy \(\dfrac{10^5+3}{10^5-2}>1\)
\(\Rightarrow B=\dfrac{10^5+3}{10^5-2}>\dfrac{10^5+3+1}{10^5-2+1}=\dfrac{10^5+4}{10^5-1}=A\)
Vậy \(B>A\)