a: 2/3=12/x

=>12/x=2/3

hay x=18

b: =>x/12=2/3

hay x=8

c: =>1/x=1/4

hay x=4

d: =>x/125=2/5

nên x=50

a, \(\dfrac{12}{18}=\dfrac{12}{x}\Rightarrow x=18\)

b, \(\dfrac{24}{36}=\dfrac{3x}{36}\Rightarrow3x=24\Leftrightarrow x=8\)

c, \(\dfrac{14}{56}=\dfrac{14}{14x}\Rightarrow14x=56\Leftrightarrow x=4\)

d, \(\dfrac{x}{125}=\dfrac{50}{125}\Rightarrow x=50\)

 x = 18

 x = 8

 x = 4

 x = 50

\(\frac{2}{3}=\frac{2.6}{3.6}=\frac{12}{18}\)

\(\frac{14}{56}=\frac{14:14}{56:14}=\frac{1}{4}\)

\(\frac{24}{36}=\frac{24:3}{36:3}=\frac{8}{12}\)

\(\frac{x}{152}=\frac{2}{5}\Rightarrow x.5=2.152\Rightarrow x.5=304\Rightarrow x=304:5=60,8\)

a)\(\frac{2}{3}=\frac{12}{x}\Rightarrow12\times3=2x\)

=>36=2x

=>x=18

b)\(\frac{14}{56}=\frac{1}{4}=\frac{1}{x}\Rightarrow4=x\)

=>x=4

c)\(\frac{24}{36}=\frac{2}{3}=\frac{x}{12}\Rightarrow12\times2=3x\)

=>24=3x

=>x=8

d)\(\frac{x}{152}=\frac{2}{5}\Rightarrow2\times152=5x\)

=>304=5x

=>x=\(\frac{304}{5}\)

a} 12/18=12/x

=> x=18

b}14/56=14/14x

=> 14x=56

=> x=56:14=4

c}24/36=3x/36

=> 3x=24

=> x=24:3

=> x=8

d} ko tồn tại vì 152 ko chia hết cho 5    

\(a)\frac{2}{3}=\frac{12}{x}\)

\(\Rightarrow2\cdot x=12\cdot3\)

\(\Rightarrow2\cdot x=36\)

\(\Rightarrow x=36:2=18\)

Vậy x = 18

\(b)\frac{24}{36}=\frac{x}{12}\)

Rút gọn : \(\frac{24}{36}=\frac{24:12}{36:12}=\frac{2}{3}\)

\(\Rightarrow\frac{2}{3}=\frac{x}{12}\)

\(\Rightarrow2\cdot12=x\cdot3\)

\(\Rightarrow x=\frac{2\cdot12}{3}=8\)

Vậy x = 8

\(c)\frac{14}{56}=\frac{1}{x}\)

Rút gọn : \(\frac{14}{56}=\frac{14:14}{56:14}=\frac{1}{4}\)

\(\Rightarrow\frac{1}{4}=\frac{1}{x}\)

\(\Rightarrow x=4\)

Vậy x = 4

\(d)\frac{x}{125}=\frac{2}{5}\)

\(\Rightarrow x\cdot5=2\cdot125\)

\(\Rightarrow x\cdot5=250\)

\(\Rightarrow x=250:5=50\)

Vậy x = 50

a) x = 18

b) x = 8

c) x = 4

d) x = 50

bạn làm dấu chấm là dấu nhân có phải không 

Bài 3: 

a: =>x/56=3/7

hay x=21

b: =>3/x=6/14

hay x=7

c: =>35/x=7/15

hay x=75

d: =>2x=-10/9

hay x=-10/18=-5/9

1.

a, 2/3=12/x

12/18=12/x

=>x=18

Vậy x=18

b, 14/56=1/x

1/4=1/x

=>x=4 

Vậy x=4

c, 24/36=x/12

2/3=x/12

8/12=x/12

=>x=8

Vậy x =8

2

38/11+4/17-5/11-3/17

=(38/11-5/11)+(4/17-3/17)

=33/11+1/17

=3+1/17

=51/17+1/17

=52/17

3.

2/7 x =2/3

x=2/3:2/7

x=2/3x7/2

x=7/3

Vậy x=7/3

2/5:x=1/3

x=2/5:1/3

x=2/5x3

x=6/5

Vậy x= 6/5

K cho mình nha bạn !!!!!!!!!!!!^^

Tớ không hiểu.  Cậu giải đi

a)\(\dfrac{24}{36}\)=\(\dfrac{8}{12}\)

b)\(\dfrac{14}{56}\)=\(\dfrac{1}{4}\)

c)\(\dfrac{9}{24}\)=\(\dfrac{21}{56}\)

Chúc bạn học tốt!

a: x/12=24/36

nên x/12=2/3

=>x=2/3x12=8

b: 1/x=14/56

nên 1/x=1/14

hay x=14

c: x/56=9/24

=>x/56=3/8

hay x=21

Chọn C