a) Ta có : \(\frac{-8}{15}=\frac{\left(-1\right)+\left(-7\right)}{15}=\frac{\left(-2\right)+\left(-6\right)}{15}=\frac{\left(-3\right)+5}{15}\)
Do đó \(\frac{-8}{15}=\frac{-1}{15}+\frac{-7}{15};\frac{-8}{15}=\frac{-2}{15}+\frac{-6}{15}=\frac{-2}{15}+\frac{-2}{5};\frac{-8}{15}=\frac{-3}{15}+\frac{-5}{15}=\frac{-1}{5}+\frac{-1}{3}\)
b) Ta có : \(\frac{-8}{15}=\frac{1-9}{15}=\frac{2-10}{15}=\frac{3-11}{15}\)
Do đó \(\frac{-8}{15}=\frac{1}{15}-\frac{9}{15}=\frac{1}{15}-\frac{3}{5};\frac{-8}{15}=\frac{2}{15}-\frac{10}{15}=\frac{2}{15}-\frac{2}{3};\frac{-8}{15}=\frac{3}{15}-\frac{11}{15}=\frac{1}{5}-\frac{11}{15}\)
c) Ta có : \(\frac{-8}{15}=\frac{9+\left(-17\right)}{15}=\frac{10+\left(-18\right)}{15}=\frac{11+\left(-19\right)}{15}\)
Do đó \(\frac{-8}{15}=\frac{9}{15}+\frac{-17}{15}=\frac{3}{5}+\frac{-17}{15}=\frac{3}{5}+\left(-1\frac{2}{15}\right);\)
\(\frac{-8}{15}=\frac{10}{15}+\frac{-18}{15}=\frac{2}{3}+\frac{-6}{5}=\frac{2}{3}+\left(-1\frac{1}{5}\right);\)
\(\frac{-8}{15}=\frac{11}{15}+\frac{-19}{15}=\frac{11}{15}+\left(-1\frac{4}{15}\right).\)
P/S : Hiếu tỉ là gì bạn ? Hữu tỉ mới đúng =))
