a: \(x_1=x_2=x_3=x_4\)

TA có : 

\(x_1=\frac{19019}{76076}=\frac{1}{4}\)

\(x_2=\frac{-1919}{-7676}=\frac{1}{4}\)

\(x_3=\frac{-19}{-76}=\frac{1}{4}\)

\(\Rightarrow x_1=x_2=x_3\)

Tập hợp các số hữu tỉ  \(A=\left\{\frac{1}{4}\right\}\)

đổi:

-213/300=-0,71

18/-25=-0,72

Vậy x>y(-0,71>-0,72)

a: \(x=\frac{2}{-5}=\frac{-2\cdot13}{5\cdot13}=\frac{-26}{65};y=\frac{-3}{13}=\frac{-3\cdot5}{13\cdot5}=\frac{-15}{65}\)

mà -26<-15

nên x<y

b: \(x=-0,375=-\frac38;y=-\frac38\)

Do đó: x=y

c: \(x=\frac{-127}{128}>-\frac{128}{128}=-1\)

\(y=-\frac{1345}{1344}<-\frac{1344}{1344}=-1\)

Do đó: x>y

d: \(x=-\frac{11}{33}=\frac{-1}{3}=\frac{-25}{75};y=\frac{25}{-76}=\frac{-25}{76}\)

Ta có: 75<76

=>\(\frac{25}{75}>\frac{25}{76}\)

=>\(\frac{-25}{75}<\frac{-25}{76}\)

=>x<y

e: \(x=\frac{-2002}{-2003}=\frac{2002}{2003}=1-\frac{1}{2003};y=\frac{1994}{1995}=1-\frac{1}{1995}\)

Ta có: 2003>1995

=>\(\frac{1}{2003}<\frac{1}{1995}\)

=>\(\frac{-1}{2003}>\frac{-1}{1995}\)

=>\(\frac{-1}{2003}+1>\frac{-1}{1995}+1\)

=>x>y

g: \(y=\frac{-171717}{232323}=\frac{-171717:10101}{232323:10101}=-\frac{17}{23}\)

=>x=y

So sánh \(\frac{-19}{49}\)và\(\frac{-23}{27}\)

Quy đồng lên ta được: \(\frac{-19}{49}=\frac{\left(-19\right).47}{49}=\frac{-893}{2303}\)và\(\frac{-23}{47}=\frac{\left(-23\right).49}{47.49}=\frac{-1127}{2303}\)

Mà: \(\frac{-893}{2303}>\frac{-1127}{2303}\)\(\Rightarrow\frac{-19}{49}>\frac{-23}{47}\)

em làm xong từ hôm qua r ạ

1. x < y 
2. x < y 
3. x = y 
4. x > y 
5. x < y
6. x < y 
7. x > y