`a)` Phân số tối giản là: \(\dfrac{2}{3};\dfrac{5}{4};\dfrac{11}{12}\)

`b)` Phân số rút gọn được là: \(\dfrac{28}{14};\dfrac{69}{54}\)

  \(\dfrac{28}{14}=\dfrac{28:14}{14:14}=2\)

 \(\dfrac{69}{54}=\dfrac{69:3}{54:3}=\dfrac{23}{18}\)

a, phân số tối giản là 2/3; 11/12; 5/4

b, phân số rút gọn được là 28/14=2; 69/54=16/9

28/14=2

36/28=9/7

88/77=8/7

45/50=9/10

120/150=4/5

\(\dfrac{28}{14}=2\)
\(\dfrac{36}{28}=\dfrac{36:4}{28:4}=\dfrac{9}{7}\)
\(\dfrac{88}{77}=\dfrac{88:11}{77:11}=\dfrac{8}{7}\)
\(\dfrac{45}{50}=\dfrac{45:5}{50:5}=\dfrac{9}{10}\)
\(\dfrac{120}{150}=\dfrac{120:30}{150:30}=\dfrac{4}{5}\)

\(\Leftrightarrow\dfrac{1}{2};\dfrac{1}{2};\dfrac{8}{5};\dfrac{3}{2}\)

14/28=1/2

25/50=1/2

48/30=8/5

81/54=3/2

11/12=1/2 , 36/10=18/5 , 75/36 = 25/12 , 14/28 = 1/2 , 48/30 = 8/5

1/2;18/5;25/12;1/2;24/15

a ) 1 3 b ) 1 4 c ) − 1 3

d ) 1 2 e ) 1 4 f ) 3 5

g ) 2 3 h ) − 3 2

\(\dfrac{14}{21}=\dfrac{7\cdot2}{7\cdot3}=\dfrac{2}{3}\)

\(\dfrac{-36}{48}=\dfrac{-12\cdot3}{12\cdot4}=-\dfrac{3}{4}\)

\(\dfrac{28}{-52}=\dfrac{7\cdot4}{-4\cdot13}=-\dfrac{7}{13}\)

\(\dfrac{-54}{-90}=\dfrac{-18\cdot3}{-18\cdot5}=\dfrac{3}{5}\)

\(\dfrac{14}{21}\) =\(\dfrac{2}{3}\)

\(\dfrac{-36}{48}\) =\(\dfrac{3}{4}\)

\(\dfrac{28}{-52}\)=\(\dfrac{7}{-13}\)

\(\dfrac{-54}{-90}\) =\(\dfrac{6}{9}=\dfrac{2}{3}\)

14/28=1/2

25/50 = 1/2

48/30= 8/5

20/30 = 2/3

14/28=1/2

15/20=1/2

48/30=8/5

20/30=2/3

b) 14/15

c)39/65

b) 14/15 ; 17/51

c) (Mình không thấy có phân số nào rút gọn được nữa)

\(n\in\left\{2;4;6;8;10;12\right\}\)

lời giải ?

\(\dfrac{4}{5}+\dfrac{1}{4}=\dfrac{21}{20}\)

=4/5+1/4=21/20