a,\(-\frac{15}{21}=-\frac{5}{7};-\frac{55}{77}=-\frac{5}{7}\Rightarrow-\frac{15}{21}=-\frac{55}{77}\)

b, \(-\frac{3737}{5151}=-\frac{37}{51};-\frac{373737}{515151}=-\frac{37}{51}\Rightarrow-\frac{3737}{5151}=-\frac{373737}{515151}\)

\(\frac{-15}{21}=\frac{-15\div3}{21\div3}=\frac{-5}{7}\)

\(\frac{-55}{77}=\frac{-55\div11}{77\div11}=\frac{-5}{7}\)

Vì \(\frac{-5}{7}=\frac{-5}{7}\Rightarrow\frac{-15}{21}=\frac{-55}{77}\)

b , \(\frac{-3737}{5151}=\frac{-3737\div101}{5151\div101}=\frac{-37}{51}\)

\(\frac{-373737}{515151}=\frac{-373737\div10101}{515151\div10101}=\frac{-37}{51}\)

Vì \(\frac{-37}{51}=\frac{-37}{51}\Rightarrow\frac{-3737}{5151}=\frac{-373737}{515151}\)

\(\frac{-151515}{232323}=\frac{-151515:10101}{232323:10101}=\frac{-15}{23}\)

\(\frac{-15151515}{23232323}=\frac{-15151515:1010101}{23232323:1010101}=\frac{-15}{23}\)

Vậy 2 phân số ngày bằng nhau

Hai phân số này bằng nhau

Vì: Hai phân số này khi rút gọn sẽ bằng nhau

vì -3737/5151=\(\frac{-37.101}{51.101}\) =-37/51

-373737  /   515151=\(\frac{-37.10101}{51.10101}\) =-37/51

=>-3737/5151=-373737/515151

ok

a,23/99 = 23.101/99.101=2323/9999

23/99 = 23.10101/99.10101=232323/999999

b, -3737/5151=-3737.101/5151.101=-373737/515151

c, tương tự thì cứ lấy phân số đầu .2 xong rồi .4

a: \(\dfrac{20}{30}=\dfrac{2}{3}\)

\(\dfrac{30}{45}=\dfrac{2}{3}\)

Do đó: \(\dfrac{20}{30}=\dfrac{30}{45}\)

b: \(\dfrac{-25}{35}=\dfrac{-5}{7}\)

\(\dfrac{-55}{77}=\dfrac{-5}{7}\)

Do đó: \(-\dfrac{25}{35}=-\dfrac{55}{77}\)

a,20/30=2/3

30/45=2/3

->20/30=30/45

b -25/35=-5/7

-55/77=-5/7

-> -25/35=-55/77

a: 20/30=2/3

30/45=2/3

=>20/30=30/45

b: -25/35=-5/7

-55/77=-5/7

=>-25/35=-55/77

a) Có -21/28 = -3/4 và -39/52 = -3/4

suy ra -21/28 = -39/52 (= -3/4)

b) Có -1717/2323 = -17/23 và -171717/232323 = -17/23

suy ra -1717/2323 = -171717/232323 (= -17/23)

nhớ cho mk nha

Vì -21/28=-3/4=-39/52