3x+1=1/2

3x=1/2-1

3x=-1/2

x=-1/2:3

x=-1/6

vậy đáp án D là đúng

tick đúng nha

\(\frac{x}{7}=\frac{x+1}{14}\Leftrightarrow14x=7x+7\Leftrightarrow7x=7\Leftrightarrow x=1\)

\(\frac{1}{2}+\frac{1}{3}+\frac{1}{6}\le x\le\frac{15}{4}+\frac{18}{8}\)

\(\Leftrightarrow1\le x\le6\Leftrightarrow x=1;2;3;4;5;6\)

\(\frac{1}{2}+\frac{-3}{5}+\frac{1}{10}\le x\le\frac{8}{3}+\frac{14}{6}\)

\(\Leftrightarrow\frac{1}{2}-\frac{3}{5}+\frac{1}{10}\le x\le\frac{8}{3}+\frac{14}{6}\)

\(\Leftrightarrow0\le x\le5\Leftrightarrow x=0;1;2;3;4;5\)

\(\frac{x}{7}=\frac{x+1}{14}\)

=> \(\frac{x\cdot2}{7\cdot2}=\frac{x+1}{14}\)

=> \(2x=x+1\)

=> \(2x-x-1=0\)

=> \(1x-1=0\)

=> \(x=1\)

\(\frac{1}{2}+\frac{1}{3}+\frac{1}{6}\le x\le\frac{15}{4}+\frac{18}{8}\)

=> \(1\le x\le6\)

=> \(x=\left\{1;2;3;4;5;6\right\}\)

\(\frac{1}{2}+\frac{-3}{5}+\frac{1}{10}\le x\le\frac{8}{3}+\frac{14}{6}\)

=> \(0\le x\le5\)

=> \(x=\left\{0;1;2;3;4;5\right\}\)

Giải:

Các cặp phân số bằng nhau lập được từ đẳng thưc 3.4 = 6.2 là :

  \(\frac{3}{6}=\frac{2}{4}\); \(\frac{6}{2}=\frac{4}{2}\); \(\frac{4}{6}=\frac{2}{3}\); \(\frac{3}{2}=\frac{6}{4}\)

 Vậy ...

đúng rồi đó

rồi,kp nha

a)\(=\frac{1}{2}\left(\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+...+\frac{1}{98}-\frac{1}{100}\right)\)

\(=\frac{1}{2}\left(\frac{1}{2}-\frac{1}{100}\right)\)

\(=\frac{1}{2}\cdot\frac{49}{100}\)

\(=\frac{49}{200}\)

b)\(=\frac{1}{4}\left(1-\frac{1}{5}+\frac{1}{5}-\frac{1}{9}+...+\frac{1}{201}-\frac{1}{205}\right)\)

\(=\frac{1}{4}\left(1-\frac{1}{205}\right)\)

\(=\frac{1}{4}\cdot\frac{204}{205}\)

\(=\frac{51}{205}\)

c)\(=3\left(\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{97}-\frac{1}{99}\right)\)

\(=3\left(\frac{1}{3}-\frac{1}{99}\right)\)

\(=3\cdot\frac{32}{99}\)

\(=\frac{32}{33}\)

d)tương tự bạn nhân với 4/3 nhé

Trả lời :

\(a,\frac{1}{6}=\frac{x}{18}\Rightarrow\frac{3}{18}=\frac{x}{18}\Rightarrow x=3\)

\(b,\frac{x}{8}=\frac{-1}{4}\Rightarrow\frac{x}{8}=\frac{-2}{8}\Rightarrow x=-2\)

\(c,\frac{4}{5}=\frac{x}{10}\Rightarrow\frac{x}{10}=\frac{8}{10}\Rightarrow x=8\)

\(d,\frac{11}{5}=\frac{-22}{x}\Rightarrow\frac{-22}{x}=\frac{-22}{10}\Rightarrow x=10\)

a) 1/6 = x/18 

1.18= 6.x

18 = 6.x

x= 18: 6

x= 3

b) x/8 = -1/4

x.4=-1.8

x.4= - 8

x=-8 :4

x = -4

c) 4/5= x/10

4 . 10= x.5

40 = x . 5

x= 40 : 5

x = 8

d)11/5 = -22/x

11.x = -22.5

11.x =-110

x = -110 : 11

x = -10

chúc bn học tốt !

Bài 1:

1) \(\frac{11}{3}\): 3\(\frac{1}{3}\)- 3

= \(\frac{11}{3}\): \(\frac{10}{3}\)- 3

= \(\frac{11}{3}\). \(\frac{3}{10}\)- 3 

= \(\frac{11}{10}\)- 3

= \(\frac{-19}{10}\)

2) \(\frac{5}{6}\):  \(\frac{3}{52}\) - \(\frac{5}{6}\). 47\(\frac{1}{3}\)

= \(\frac{5}{6}\) . \(\frac{52}{3}\)- \(\frac{5}{6}\). 47\(\frac{1}{3}\)

= \(\frac{5}{6}\).(\(\frac{52}{3}\)- 47\(\frac{1}{3}\))

= \(\frac{5}{6}\).( -30)

= -25

mách mình mấy câu kia với