a, \(\dfrac{4x}{7}=\dfrac{1}{5}+\dfrac{2}{3}=\dfrac{3+10}{15}=\dfrac{13}{15}\Rightarrow60x=91\Leftrightarrow x=\dfrac{91}{60}\)

b, \(\dfrac{5}{7}:x=\dfrac{1}{6}+\dfrac{4}{5}=\dfrac{5+24}{30}=\dfrac{29}{30}\Leftrightarrow x=\dfrac{5}{7}:\dfrac{29}{30}=\dfrac{150}{203}\)

giúp mình với đi mà

\(a.y:\dfrac{2}{3}=\dfrac{4}{9}\times3\\y:\dfrac{2}{3}=\dfrac{4}{3}\\ y=\dfrac{4}{3}\times\dfrac{2}{3}\\ y=\dfrac{8}{9}\\ b.\dfrac{5}{6}+\dfrac{y}{12}=\dfrac{7}{6}\\ \dfrac{y}{12}=\dfrac{7}{6}-\dfrac{5}{6}\\ \dfrac{y}{12}=\dfrac{2}{6}\\ y\times6=12\times2=24\\ y=24:6\\ y=4 \)

\(a,y:\dfrac{2}{3}=\dfrac{4}{9}.3\)

\(y:\dfrac{2}{3}=\dfrac{4}{3}\)

\(y=\dfrac{4}{3}.\dfrac{2}{3}\)

\(y=\dfrac{8}{9}\)

\(b,\dfrac{5}{6}+\dfrac{y}{12}=\dfrac{7}{6}\)

\(\dfrac{y}{12}=\dfrac{7}{6}-\dfrac{5}{6}\)

\(\dfrac{y}{12}=\dfrac{2}{6}\)

\(y.6=12.2\)

\(y.6=24\)

\(y=24:6\)

\(y=4\)

a: 14/5-7/5=7/5

b: 7/8-1/3+5/4

=21/24-8/24+30/24

=43/24

c; =7/6+5/6+2/15+13/15

=2+1

=3

d: =4*5/3*11=20/33

e: =2/9*1/6*1/4=2/9*1/24=1/108

2:
a: \(=\dfrac{3}{9}\cdot\dfrac{4}{4}\cdot\dfrac{5}{5}\cdot\dfrac{6}{6}\cdot\dfrac{7}{7}=\dfrac{1}{3}\)

b: \(=\dfrac{1}{6}\left(\dfrac{22}{3}-\dfrac{2}{3}\right)=\dfrac{10}{3}\cdot\dfrac{1}{6}=\dfrac{10}{18}=\dfrac{5}{9}\)

c; \(=\dfrac{1}{3}\left(9-\dfrac{2}{5}-\dfrac{3}{5}\right)=\dfrac{8}{3}\)

14/5-7/5=7/5 

7/8-1/3+5/4=13/24+5/4=43/24 

7/6+2/15+5/6+13/15=13/10+5/6+13/15=32/15+13/15=3

4/3*5/11=20/35

2/9:6*1/4=1/27*1/4=1/108

\(15/35; 28/35\)

\(14/24; 9/24\)

\(9/15; 5/15\)

\(22/18; 21/18\) nhé =)

câu 1: 15/35 và 28/35

câu2: 14/24và9/24

câu 3: 9/15và5/15

câu 4: 22/18và21/18

làm đầy đủ được ko mọi người

`3/7 xx 1/9 + 3/7 xx 8/9`

`= 3/7 xx (1/9 +8/9)`

`= 3/7 xx 9/9`

`= 3/7 xx 1`

`=3/7`

\(\dfrac{3}{7}\times\dfrac{1}{9}+\dfrac{3}{7}\times\dfrac{8}{9}\)

\(=\dfrac{3}{7}\times\left(\dfrac{1}{9}+\dfrac{8}{9}\right)\)

\(=\dfrac{3}{7}\times1\)

\(=\dfrac{3}{7}\)

`3/7xx1/9+3/7xx8/9`

`=3/7xx(1/9+8/9)`

`=3/7xx9/9`

`=3/7xx1`

`=3/7`

=(-2)+(-2)+...+(-2)

=-2x11

=-22

66/54 và 63/54 nhé =)

66/54 và 63/54 

làm đầy đủ được ko mọi người đừng ghi kết quả ko ạ

\(=\left(-\dfrac{3}{4}+\dfrac{3}{4}\right)+\left(\dfrac{2}{5}+\dfrac{3}{5}\right)-\dfrac{1}{2}=1-\dfrac{1}{2}=\dfrac{1}{2}\)

\(\dfrac{3}{-4}+\dfrac{-3}{-4}+\dfrac{2}{5}+\dfrac{-1}{2}+\dfrac{3}{5}\\ =\left(\dfrac{-3}{4}+\dfrac{3}{4}\right)+\left(\dfrac{2}{5}+\dfrac{3}{5}\right)-\dfrac{1}{2}\\ =0+1-\dfrac{1}{2}\\ =1-\dfrac{1}{2}\\ =\dfrac{1}{2}\)