Question

[Phương Bảo]

 giải giúp e

Answer 1

[Nguyễn Thị Thương Hoài]

Bài 1: 

a; \(\dfrac{5}{4}\); \(\dfrac{-3}{25}\); \(\dfrac{7}{50}\)

4 = 2²; 25 = 5²; 50 = 2.5²

BCNN(4; 25; 50) = 2².5² = 100

\(\dfrac{5}{4}\) = \(\dfrac{5.25}{4.25}\) = \(\dfrac{125}{100}\) ; \(\dfrac{-3}{25}\) = \(\dfrac{-3.4}{25.4}\) = \(\dfrac{-12}{100}\); \(\dfrac{7}{50}\) = \(\dfrac{7.2}{50.10}\) = \(\dfrac{14}{100}\)

b; \(\dfrac{-7}{20}\); \(\dfrac{9}{10}\); \(\dfrac{-13}{30}\)

20 = 2².5; 10 = 2.5; 30 = 2.3.5;  BCNN(20;10;30) = 2².3.5 = 60

\(\dfrac{-7}{20}\) = \(\dfrac{-7.3}{20.3}\) = \(\dfrac{-21}{60}\); \(\dfrac{9}{10}\) = \(\dfrac{9.6}{10.6}\) = \(\dfrac{54}{60}\); \(\dfrac{-13}{30}\) = \(\dfrac{-13.2}{30.2}\) = \(\dfrac{-26}{60}\)

c; \(\dfrac{7}{16}\); \(\dfrac{13}{-18}\); \(\dfrac{-11}{-12}\)

16 = 2⁴; 18 = 2.3²; 12 = 2².3

BCNN(16; 18; 12) = 2⁴.3² = 144 

\(\dfrac{7}{16}\) = \(\dfrac{7.9}{16.9}\) = \(\dfrac{63}{144}\);

\(\dfrac{13}{-18}\) = \(\dfrac{-13}{18}\) = \(\dfrac{-13.8}{18.8}\) = \(\dfrac{-104}{144}\)

\(\dfrac{-11}{-12}\) = \(\dfrac{11}{12}\) = \(\dfrac{11.12}{12.12}\) = \(\dfrac{132}{144}\)