\(a,\dfrac{52}{32}=\dfrac{13}{8}\\ \dfrac{55}{65}=\dfrac{11}{13}\\ MSC:104\\ =>\dfrac{13}{8}=\dfrac{13.13}{8.13}=\dfrac{169}{104}\\ \dfrac{11}{13}=\dfrac{11.8}{13.8}=\dfrac{88}{104}\)

\(b,\dfrac{72}{64}=\dfrac{9}{8}\\ \dfrac{54}{81}=\dfrac{2}{3}\\ MSC:24\\ \dfrac{9}{8}=\dfrac{9.3}{8.3}=\dfrac{27}{24}\\ \dfrac{2}{3}=\dfrac{2.8}{3.8}=\dfrac{16}{24}\\ c,\dfrac{24}{36}=\dfrac{2}{3}\\ \dfrac{12}{30}=\dfrac{2}{5}\\ MSC:15\\ \dfrac{2}{3}=\dfrac{2.5}{3.5}=\dfrac{10}{15}\\ \dfrac{2}{5}=\dfrac{2.3}{3.5}=\dfrac{6}{15}\)

\(d,\dfrac{80}{40}=2\\ \dfrac{45}{63}=\dfrac{5}{7}\\ MSC:7\\ 2=\dfrac{14}{7}\\ e,\dfrac{150}{50}=3\\ \dfrac{100}{200}=\dfrac{1}{2}\\ MSC:2\\ 3=\dfrac{6}{2}\\ f,\dfrac{54}{81}=\dfrac{2}{3}\\ \dfrac{69}{93}=\dfrac{23}{21}\\ MSC:21\\ \dfrac{2}{3}=\dfrac{2.7}{3.7}=\dfrac{14}{21}\)

\(a.\dfrac{52}{32}\text{=}\dfrac{13}{8};\dfrac{55}{65}\text{=}\dfrac{11}{13}\)

\(\dfrac{13.13}{13.8}\text{=}\dfrac{169}{104};\dfrac{11.8}{13.8}\text{=}\dfrac{88}{104}\)

\(c.\dfrac{24}{36}\text{=}\dfrac{2}{3};\dfrac{12}{30}\text{=}\dfrac{2}{5}\)

\(\dfrac{2.5}{3.5}\text{=}\dfrac{10}{15};\dfrac{2.3}{5.3}\text{=}\dfrac{6}{15}\)

\(b.\dfrac{72}{64}\text{=}\dfrac{9.3}{8.3}\text{=}\dfrac{27}{24};\dfrac{54}{81}\text{=}\dfrac{2.8}{3.8}\text{=}\dfrac{16}{24}\)

\(d.\dfrac{80}{40}\text{=}\dfrac{2.63}{63}\text{=}\dfrac{126}{63};\dfrac{45}{63}\)

\(e.\dfrac{150}{50}\text{=}\dfrac{3.2}{2}\text{=}\dfrac{6}{2};\dfrac{100}{200}\text{=}\dfrac{1}{2}\)

\(f.\dfrac{54}{81}\text{=}\dfrac{2.31}{3.31}\text{=}\dfrac{62}{93};\dfrac{69}{93}\)

Có cái nịt nhá

\(MSC:72\)

\(\dfrac{9}{12}=\dfrac{9\times6}{12\times6}=\dfrac{54}{72}\)

\(\dfrac{24}{36}=\dfrac{24\times2}{36\times2}=\dfrac{48}{72}\)

\(\dfrac{3}{8}=\dfrac{3\times9}{8\times9}=\dfrac{27}{72}\)

9/12=36/48

24/36=2/3=32/48

3/8=18/48

a; \(\dfrac{-12}{30}\) = \(\dfrac{-2}{5}\) = \(\dfrac{-2.4}{5.4}\) = \(\dfrac{-8}{20}\)

    \(\dfrac{18}{-40}\) = \(\dfrac{9}{20}\)

b; \(\dfrac{-12}{81}\) = \(\dfrac{-4}{27}\); \(\dfrac{36}{64}\) = \(\dfrac{9}{16}\); \(\dfrac{25}{-10}\) = \(\dfrac{-5}{2}\)

   27 = 3³; 16 = 2⁴; 2 = 2

BCNN(27; 16; 2) = 2⁴.3³= 432

\(\dfrac{-12}{81}\) = \(\dfrac{-4}{27}\) = \(\dfrac{-4.16}{27.16}\) = \(\dfrac{-64}{432}\)

\(\dfrac{36}{64}\) = \(\dfrac{9}{16}\) = \(\dfrac{9.27}{16.27}\) = \(\dfrac{243}{432}\)

\(\dfrac{25}{-10}\) = \(\dfrac{-5}{2}\)= \(\dfrac{-5.216}{2.216}\) = \(\dfrac{-1080}{432}\)

a)12/21 và 3/21
b)12/36 và 15/36
c)63/56 và 48/56
Chúc bạn học tốt

a: \(\dfrac{5}{7}=\dfrac{5\cdot11}{7\cdot11}=\dfrac{55}{77}\)

\(\dfrac{9}{11}=\dfrac{9\cdot7}{11\cdot7}=\dfrac{63}{77}\)

b: \(\dfrac{36}{42}=\dfrac{6}{7}=\dfrac{6\cdot9}{7\cdot9}=\dfrac{54}{63}\)

\(-\dfrac{12}{54}=\dfrac{-2}{9}=\dfrac{-2\cdot7}{9\cdot7}=-\dfrac{14}{63}\)

c: \(\dfrac{-11}{30}=\dfrac{-11\cdot4}{30\cdot4}=\dfrac{-44}{120}\)

\(\dfrac{-17}{-40}=\dfrac{17}{40}=\dfrac{17\cdot3}{40\cdot3}=\dfrac{51}{120}\)

d: \(\dfrac{36}{42}=\dfrac{6}{7}=\dfrac{6\cdot3}{7\cdot3}=\dfrac{18}{21}\)

\(\dfrac{-12}{36}=\dfrac{-1}{3}=\dfrac{-1\cdot7}{3\cdot7}=\dfrac{-7}{21}\)

#\(N\)

`a, MSC: 12`

`2/3 =`\(\dfrac{2\times4}{3\times4}=\dfrac{8}{12}\)

`b, MSC: 36`

\(\dfrac{4}{9}=\dfrac{4\times4}{9\times4}=\dfrac{16}{36}\)

`c, MSC: 35`

\(\dfrac{6}{7}=\dfrac{6\times5}{7\times5}=\dfrac{30}{35}\)

`a, MSC: 12`

`2/3=(2xx4)/(3xx4)=8/12 ; 5/12`

`b,MSC:36`

`4/9=(4xx4)/(9xx4)=16/36;5/36`

`c,MSC:35`

`3/35 ; 6/7=(6xx5)/(7xx5)=30/35`