Question

giải thích tại sao các phân số sau đây lại bằng nhau

a) \(\frac{-15}{21}=\frac{-55}{77}\)                          b) \(\frac{-3737}{5151}=\frac{-373737}{515151}\)

Answer 1

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

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

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