Đầu tiên ta thấy : \(\dfrac{11}{6}>0\) vì đó là số hữu tỉ dương.

\(\dfrac{8}{-9}=\dfrac{-8}{9}< 0\) vì đó là số hữu tỉ âm.

Do đó : \(\dfrac{11}{6}>\dfrac{8}{-9}\)

\(\dfrac{11}{6}>0\)

\(\dfrac{8}{-9}< 0\)

\(\Rightarrow\dfrac{11}{6}>\dfrac{8}{-9}\)

Vì \(\dfrac{11}{6}>1>\dfrac{-8}{9}\) nên \(\dfrac{11}{6}>\dfrac{8}{-9}\)

Vd 3:

a) 9/10 > 5/42                                        b) -4/27 < 10/-73

Vd 4:

5/-6: -7/12; 5/8; 3/4

Vd 5:

x<y

Vd 6:

-16/27= -16/27> -16/29

1)

-2/15 < 0 

-10/-11 > 0

nên x < y

2) 

ví dụ 1 < 2 => -1 > -2

ta có 16/29 < 16/27 < 19/27 

suy ra -16/29 > -16/27 > -19/27

a,

Ta có:
\(\dfrac{3}{7}=1-\dfrac{4}{7}\)
\(\dfrac{11}{15}=1-\dfrac{4}{15}\)
So sánh phân số \(\dfrac{4}{7}\) và \(\dfrac{4}{15}\)
Vì \(7< 15\) nên \(\dfrac{1}{7}>\dfrac{1}{15}\)
\(\Rightarrow1-\dfrac{4}{7}< 1-\dfrac{4}{15}\)
Vậy \(\dfrac{3}{7}< \dfrac{11}{15}\)

b)

\(\dfrac{-11}{6}< -1< \dfrac{-8}{9}\) nên \(\dfrac{-11}{6}< \dfrac{-8}{9}\)

c) 

\(\dfrac{305}{25}=\dfrac{305:5}{25:5}=\dfrac{61}{5}\)
Ta có: 
Mẫu số chung 2 phân số: 80
\(\dfrac{297}{16}=\dfrac{297*5}{16*5}=\dfrac{1485}{80}\)
\(\dfrac{61}{5}=\dfrac{61*16}{5*16}=\dfrac{976}{80}\)
Vì \(1485>976\) nên\(\dfrac{1485}{80}>\dfrac{976}{80}\)
Vậy \(\dfrac{297}{16}>\dfrac{305}{25}\)

d,

$\frac{-205}{317}=\frac{-205:-1}{317:-1}=\frac{205}{-317}$
Ta có: 
Mẫu số chung 2 phân số: -35187
\(\dfrac{205}{-317}=\dfrac{205*111}{-317*111}=\dfrac{22755}{-35187}\)
\(\dfrac{-83}{111}=\dfrac{-83*-317}{111*-317}=\dfrac{26311}{-35187}\)
Vì \(22755< 26311\) nên\(\dfrac{22755}{-35187}< \dfrac{26311}{-35187}\)
Vậy \(\dfrac{-205}{317}< \dfrac{-83}{111}\)

Câu d, mình làm sai, cho mình sửa lại:

\(\dfrac{-205}{317}=\dfrac{-22755}{35187}\)

\(\dfrac{-83}{111}=\dfrac{-26311}{35187}\)

Vậy là  \(-22755>-26311\) hay \(\dfrac{-205}{317}>\dfrac{-83}{111}\)

a: \(x_1=x_2=x_3=x_4\)

\(\frac{11}{13}\)và \(\frac{22}{27}\)

Ta có:

\(\frac{11}{13}=\frac{297}{351}\)

\(\frac{22}{27}=\frac{242}{351}\)

Mà: \(\frac{297}{351}>\frac{242}{351}\)

Vậy \(\frac{11}{13}>\frac{22}{27}\)

\(\frac{-5}{11}\)và \(\frac{-9}{23}\)

Ta có:

\(\frac{-5}{11}=\frac{-115}{253}\)

\(\frac{-9}{23}=\frac{-99}{253}\)

Mà: \(\frac{-115}{253}< \frac{-99}{253}\)

Vậy \(\frac{-5}{11}< \frac{-9}{23}\)

bạ tự là đi minh mới lớp 6 nhá