a: -15/37>-25/37

b: -13/21=-26/42

-9/14=-27/42

mà -26>-42

nên -13/21>-9/14

c: -49/-63=7/9

56/80=7/10

=>-49/-63>56/80

d: 3/14=1-11/14

4/15=1-11/15

mà 11/14>11/15

nên 3/14<4/15

a) Ta có: \(\dfrac{15}{7}>1\) (tử lớn hơn mẫu)

\(\dfrac{9}{14}< 1\) (tử nhỏ hơn mẫu)

Vậy: \(\dfrac{15}{7}>\dfrac{9}{14}\)

b) Ta có: 

\(\dfrac{899}{900}=1-\dfrac{1}{900}\)

\(\dfrac{1235}{1236}=1-\dfrac{1}{1236}\)

Mà: \(\dfrac{1}{900}>\dfrac{1}{1236}\)

Vậy: \(\dfrac{1235}{1236}>\dfrac{899}{900}\)

c) Ta có:

\(\dfrac{77}{75}=1+\dfrac{2}{75}\)

\(\dfrac{37}{35}=1+\dfrac{2}{35}\)

Mà: \(\dfrac{2}{75}< \dfrac{2}{35}\)

Vậy: \(\dfrac{37}{35}>\dfrac{77}{75}\)

\(\left\{{}\begin{matrix}\dfrac{15}{7}=\dfrac{30}{14}\\\dfrac{9}{14}< \dfrac{30}{14}\end{matrix}\right.\Rightarrow\dfrac{15}{7}>\dfrac{9}{14}\)

\(\left\{{}\begin{matrix}\dfrac{899}{900}=\dfrac{899.1236}{900.1236}=\dfrac{\text{1111164}}{900.1236}\\\dfrac{1235}{1236}=\dfrac{1235.900}{900.1236}=\dfrac{\text{1111500}}{900.1236}>\dfrac{\text{1111164}}{900.1236}\end{matrix}\right.\Rightarrow\dfrac{1235}{1236}>\dfrac{899}{900}\)

\(\left\{{}\begin{matrix}\dfrac{77}{75}=\dfrac{539}{525}\\\dfrac{37}{35}=\dfrac{555}{525}>\dfrac{539}{525}\end{matrix}\right.\Rightarrow\dfrac{77}{73}< \dfrac{37}{35}\)

\(\sqrt{37}>6\)

\(-\sqrt{14}>-\sqrt{15}\)

=> \(\sqrt{37}-\sqrt{14}>6-\sqrt{15}\)

\(\sqrt{27}-\sqrt{14}>6-\sqrt{15}\)

- Các phân số bé hơn 1 là:

- Các phân số lớn hơn 1 là:

- Phân số:= 1

bé hơn hai

vì  71^35 . 71^15 > 37^15

=> 71^50 > 37^15

a: -3/4=-9/12

-5/6=-10/12

mà -9>-10

nên -3/4>-5/6

b: -5/17<0<2/7

c: 11/10>1>9/14