\(a,\\ =\dfrac{5}{4}-\dfrac{3}{4}=\dfrac{2}{4}=\dfrac{1}{2}\\ b,\\ =\dfrac{2}{3}-\dfrac{2}{5}=\dfrac{10-6}{15}=\dfrac{4}{15}\\ c,\\ =\dfrac{5}{6}-\dfrac{1}{4}=\dfrac{20-6}{24}=\dfrac{14}{24}=\dfrac{7}{12}\\ d,\\ =\dfrac{4}{3}-\dfrac{1}{4}=\dfrac{12-3}{12}=\dfrac{9}{12}=\dfrac{3}{4}\)

 cảm ơn chị ạ

2/3 ; 3/4; 3/2; 107/42; 1/3; 1/2

2/3 ; 3/4 ; 3/2 ; 107/42  ; 1/3 ; 1/2

8/12=2/3

9/12=3/4

 72/48 =3/2

 321/126=

75/225=1/3

23/46= 1/2

\(3;\dfrac{-1}{5};\dfrac{-1}{3}\)

\(\dfrac{-12}{-4}=\dfrac{-3}{-1}\)

\(\dfrac{7}{-35}=\dfrac{1}{-5}\)

\(\dfrac{-9}{27}=\dfrac{-1}{3}\)

\(\dfrac{{ - 12}}{{ - 4}} = \dfrac{{ - 12:\left( { - 4} \right)}}{{\left( { - 4} \right):\left( { - 4} \right)}} = 3\)

\(\dfrac{7}{{ - 35}} = \dfrac{{7:\left( { - 7} \right)}}{{ - 35:\left( { - 7} \right)}} = \dfrac{{ - 1}}{5}\)

\(\dfrac{{ - 9}}{{27}} = \dfrac{{ - 9:9}}{{27:9}} = \dfrac{{ - 1}}{3}\)

\(\frac{9}{12}=\frac{3}{4}\)

Vì \(\frac{9}{12}=\frac{9:3}{12:3}=\frac{3}{4}\)

Chúc bạn học tốt!

bằng \(\frac{3}{4}\)lấy tử vs mẫu chia 3 là ra

\(\frac{9}{12}=\frac{3}{4}\)

4/6=2/3

9/12=3/4

10/20=1/2

8/18=4/9

          BẠN CHO MÌNH NHA

2/3 ; 3/4 ; 1/2 ; 4/9

ủng hộ mình lên 100 nha

\(\frac{4}{6}=\frac{4:2}{6:2}=\frac{2}{3};\frac{9}{12}=\frac{9:3}{12:3}=\frac{3}{4};\frac{10}{20}=\frac{10:10}{20:10}=\frac{1}{2};\frac{8}{18}=\frac{8:2}{18:2}=\frac{4}{9}\) 

a)  − 3 4

b)  − 3 4

\(\frac{1+2+3+4+...+8+9}{11+12+...+18+19}\)

\(\Rightarrow\frac{\left(1+9\right).9:2}{\left(11+9\right).9:2}=\frac{1+9}{11+19}=\frac{10}{30}=\frac{1}{3}\)