Đáp án:
a) $\frac{-6}{36},\frac{-4}{36},\frac{-3}{36}$
b) $\frac{8}{12},\frac{-3}{12},\frac{-10}{12}$
Giải thích các bước giải:
a) $\frac{-1}{6},\frac{1}{-9}=\frac{-1}{9},\frac{-1}{12}\\
6=2.3\\
9=3^2\\
12=2^2.3\\
BCNN(6,9,12)=2^2.3^2=36\\
\frac{-1}{6}=\frac{-1.6}{6.6}=\frac{-6}{36}\\
\frac{-1}{9}=\frac{-4}{9.4}=\frac{-4}{36}\\
\frac{-1}{12}=\frac{-3}{12.3}=\frac{-3}{36}\\$
Vậy $\frac{-6}{36},\frac{-4}{36},\frac{-3}{36}$
b) $\frac{2}{3},\frac{1}{-4}=\frac{-1}{4},\frac{-5}{6}\\
3=3\\
4=2^2\\
6=2.3\\
BCNN(3,4,6)=2^2.3=12\\
\frac{2}{3}=\frac{2.4}{3.4}=\frac{8}{12}\\
\frac{-1}{4}=\frac{-3}{4.3}=\frac{-3}{12}\\
\frac{-5}{6}=\frac{-5.2}{6.2}=\frac{-10}{12}$
Vậy $\frac{8}{12},\frac{-3}{12},\frac{-10}{12}$
