Question

quy đồng phân số sau7/30;9/-10;3/25.

Answer 1

\(MSC=150\\ \dfrac{7}{30}=\dfrac{7.5}{30.5}=\dfrac{35}{150}\\ \dfrac{9}{-10}=\dfrac{9.\left(-15\right)}{\left(-10\right).\left(-15\right)}=\dfrac{-135}{150}\\ \dfrac{3}{25}=\dfrac{3.6}{25.6}=\dfrac{18}{150}\)

Answer 2

7/30=14/60;9/-10=18/-20;3/25=6/50

 

Answer 3

\(\dfrac{7}{30}\); \(\dfrac{9}{-10}\) = \(\dfrac{-9}{10}\); \(\dfrac{3}{25}\)

Ta có : 30 = 2 . 3 . 5 

            10 = 2 . 5

            25 = 5²

⇒ BCNN(30, 10, 25) = 2 . 3 . 5² = 150

⇒ MSC = 150

⇒ \(\dfrac{7}{30}\) = \(\dfrac{7.5}{30.5}\) = \(\dfrac{35}{150}\)

    \(\dfrac{-9}{10}\) = \(\dfrac{-9.15}{10.15}\) = \(\dfrac{-135}{150}\)

    \(\dfrac{3}{25}\) = \(\dfrac{3.6}{25.6}\) = \(\dfrac{18}{150}\)