a,-15/21=-5/7

   -55/77=-5/7

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

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

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

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

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

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

-3737/5151=-3737:101/5151:101=-37/51

\(\frac{-37}{51}\)

-3737/5151= -37/51

3/6

12/24

24/48

3737/9999=37/99 vì lấy 2 số này chia 101

\(\frac{373737}{393939}+\frac{5151}{5252}+\frac{11}{-13}=\frac{10101\times37}{10101\times39}+\frac{101\times51}{101\times52}+\frac{11}{-13}=\frac{37}{39}+\frac{51}{52}+\frac{-11}{13}\)

đến đây thì rất dễ quy đồng mẫu và tính ra kết quả, bn tự làm nhé

=\(\frac{13}{12}\). Chuẩn nhe

giải:

\(\frac{373737}{393939}=\frac{37}{39};\frac{5151}{5252}=\frac{51}{52}\)\(\Rightarrow\frac{37}{39}+\frac{51}{52}+\frac{11}{\left(-13\right)}=\frac{13}{12}\)

đúng chuẩn rồi!