Question

Quy đồng mẫu số: -54/ 72 ;42/36; 2/-3

Answer 1

\(\dfrac{-54}{72}=\dfrac{-3}{4}\); \(\dfrac{42}{36}=\dfrac{7}{6}\);  \(\dfrac{2}{-3}=\dfrac{2}{-3}\)

\(\Rightarrow BCNN\left(4,6,-3\right)=12\)

Quy đồng

\(\dfrac{-3}{4}=\dfrac{-3.3}{4.3}=\dfrac{-9}{12}\)

\(\dfrac{7}{6}=\dfrac{7.2}{6.2}=\dfrac{14}{12}\)

\(\dfrac{2}{-3}=\dfrac{2.\left(-4\right)}{\left(-3\right).\left(-4\right)}=\dfrac{-8}{12}\)