\(\dfrac{1}{2}x+0,2x-x-\dfrac{1}{5}=2\dfrac{3}{5}\\ \dfrac{1}{2}x+0,2x-x-\dfrac{1}{5}=\dfrac{13}{5}\\ x\cdot\left(\dfrac{1}{2}+0,2-1\right)=\dfrac{14}{5}\\ x\cdot\left(\dfrac{5}{10}+\dfrac{2}{10}+\dfrac{10}{10}\right)=\dfrac{14}{5}\\ x\cdot\dfrac{17}{10}=\dfrac{14}{5}\\ x=\dfrac{14}{5}:\dfrac{17}{10}\\ x=\dfrac{14}{5}\cdot\dfrac{10}{17}\\ x=\dfrac{28}{17}\)

b) \(\dfrac{4}{5}-\dfrac{3}{4}:x=0,3\)

\(\Rightarrow0,8-0,75:x=0,3\)

\(\Rightarrow0,75:x=0,5\)

\(\Rightarrow x=1,5\)

c) \(\dfrac{-3}{2}-\dfrac{1}{4}x=1\dfrac{1}{3}-0,2x\)

\(\Rightarrow\dfrac{-3}{2}-\dfrac{4}{3}=\dfrac{1}{4}x-\dfrac{1}{5}x\)

\(\Rightarrow x=\dfrac{-17}{6}\cdot20\)

\(\Rightarrow x=\dfrac{-170}{3}\)

d) \(\left|\dfrac{3}{5}x+\dfrac{4}{3}\right|:\dfrac{2}{3}-0,5=1\dfrac{1}{2}\)

\(\Rightarrow\left|\dfrac{3}{5}x+\dfrac{4}{3}\right|:\dfrac{2}{3}=\dfrac{3}{2}+\dfrac{1}{2}\)

.\(\Rightarrow\left|\dfrac{3}{5}x+\dfrac{4}{3}\right|=\dfrac{4}{3}\)

\(\Rightarrow\left[{}\begin{matrix}\dfrac{3}{5}x+\dfrac{4}{3}=\dfrac{4}{3}\Rightarrow x=0\\\dfrac{3}{5}x+\dfrac{4}{3}=-\dfrac{4}{3}\Rightarrow x=\dfrac{-40}{9}\end{matrix}\right.\)

a, \(2,5:4x=0,5:0,2\)

\(\Rightarrow4x=\dfrac{2,5.0,2}{0,5}\)

\(\Rightarrow4x=1\Rightarrow x=\dfrac{1}{4}\)

b, \(\dfrac{1}{5}x:3=\dfrac{2}{3}:0,5\)

\(\Rightarrow\dfrac{1}{5}x=\dfrac{3.\dfrac{2}{3}}{0,5}\)

\(\Rightarrow\dfrac{1}{5}x=4\Rightarrow x=20\)

c, \(1,25:0,8=\dfrac{3}{8}:0,2x\)

\(\Rightarrow0,2x=\dfrac{0,8.\dfrac{3}{8}}{1,25}\)

\(\Rightarrow0,2x=0,24\Rightarrow x=1,2\)

Chúc bạn học tốt!!

a, \(2,5:4x=0,5:0,2\)

\(2,5:4x=2,5\)

\(4x=2,5:2,5\)

\(4x=1\)

\(x=1:4\)

\(x=\dfrac{1}{4}\)

Vậy .............

b, \(\dfrac{1}{5}x:3=\dfrac{2}{3}\)

\(\dfrac{1}{5}x=\dfrac{2}{3}.3\)

\(\dfrac{1}{5}x=2\)

\(x=2:\dfrac{1}{5}\)

\(x=10\)

Vậy .....

c, \(1,25:0,8=\dfrac{3}{8}:0,2x\)

\(1,5625=\dfrac{3}{8}:0,2x\)

\(0,2x=\dfrac{3}{8}:1,5625\)

\(0,2x=0,24\)

\(x=0,24:0,2\)

\(x=1,2\)

Vậy ...

a) \(2,5:4x=0,5:0,2\)

\(\Rightarrow2,5:4x=2,5\)

\(\Rightarrow4x=1\)

\(\Rightarrow x=0,25\)

b) \(\dfrac{1}{5}x:3=\dfrac{2}{3}:0,25\)

\(\Rightarrow\dfrac{1}{5}x:3=\dfrac{8}{3}\)

\(\Rightarrow\dfrac{1}{5}x=8\)

\(\Rightarrow x=40\)

c) \(1,25:0,8=\dfrac{3}{8}:0,2x\)

\(\Rightarrow\dfrac{3}{8}:0,2x=1,5625\)

\(\Rightarrow0,2x=0,24\)

\(\Rightarrow x=1,2\)

Không có dấu "=" hay như nào đâu giải tìm x được

a)4/5+x=2/3

x=2/3-4/5

x=-2/15

b)-5/6-x=2/3

x=-5/6-2/3

x=-3/2

c)1/2x+3/4=-3/10

1/2x=-3/10-3/4

1/2x=-21/20

x=-21/20:1/2

x=-21/10

d)x/3-1/2=1/5

x/3=1/5+1/2

x/3=7/10

10x/30=21/30

10x=21

x=21:10

x=21/10

\(x-\dfrac{1}{2}=\dfrac{3}{4}\)

\(x=\dfrac{3}{4}+\dfrac{1}{2}\)

\(x=\dfrac{5}{4}\)

\(x+\dfrac{7}{8}=\dfrac{3}{4}\)

\(x=\dfrac{3}{4}-\dfrac{7}{8}\)

\(x=\dfrac{-1}{8}\)

\(\dfrac{1}{2}\cdot x-\dfrac{1}{4}=\dfrac{-1}{2}\)

\(\dfrac{1}{2}\cdot x=\dfrac{-1}{2}+\dfrac{1}{4}\)

\(\dfrac{1}{2}\cdot x=\dfrac{-1}{4}\)

\(x=\dfrac{-1}{4}\div\dfrac{1}{2}\)

\(x=\dfrac{-1}{2}\)

Câu D ko bt

`@` `\text {Ans}`

`\downarrow`

`a)`

\(\dfrac{3}{2}\times\dfrac{4}{5}-x=\dfrac{2}{3}\)

\(\dfrac{6}{5}-x=\dfrac{2}{3}\)

\(x=\dfrac{6}{5}-\dfrac{2}{3}\)

\(x=\dfrac{18}{15}-\dfrac{10}{15}\)

\(x=\dfrac{8}{15}\)

Vậy, `x =`\(\dfrac{8}{15}\)

`b)`

\(x\times3\dfrac{1}{3}=3\dfrac{1}{3}\div4\dfrac{1}{4}\)

\(x\times\dfrac{10}{3}=\dfrac{40}{51}\)

\(x=\dfrac{40}{51}\div\dfrac{10}{3}\)

\(x=\dfrac{4}{17}\)

Vậy, \(x=\dfrac{4}{17}\)

`c)`

\(5\dfrac{2}{3}\div x=3\dfrac{2}{3}-2\dfrac{1}{2}\)

\(\dfrac{17}{3}\div x=\dfrac{7}{6}\)

\(x=\dfrac{17}{3}\div\dfrac{7}{6}\)

\(x=\dfrac{34}{7}\)

Vậy, `x = `\(\dfrac{34}{7}\)

a) \(\dfrac{3}{2}x\dfrac{4}{5}-x=\dfrac{2}{3}\Rightarrow\dfrac{6}{5}-x=\dfrac{2}{3}\Rightarrow x=\dfrac{6}{5}-\dfrac{2}{3}=\dfrac{18}{15}-\dfrac{10}{15}=\dfrac{8}{15}\)

b) \(x.3\dfrac{1}{3}=3\dfrac{1}{3}:4\dfrac{1}{4}\Rightarrow\dfrac{10}{3}.x=\dfrac{10}{3}:\dfrac{17}{4}\Rightarrow\dfrac{10}{3}.x=\dfrac{10}{3}.\dfrac{4}{17}\Rightarrow x=\dfrac{10}{3}.\dfrac{4}{17}:\dfrac{10}{3}=\dfrac{10}{3}.\dfrac{4}{17}.\dfrac{3}{10}=\dfrac{4}{17}\)

c) \(5\dfrac{2}{3}:x=3\dfrac{2}{3}-2\dfrac{1}{2}\Rightarrow\dfrac{17}{3}:x=\dfrac{11}{3}-\dfrac{5}{2}\Rightarrow\dfrac{17}{3}:x=\dfrac{22}{6}-\dfrac{15}{6}\Rightarrow\dfrac{17}{3}:x=\dfrac{7}{6}\Rightarrow x=\dfrac{17}{3}:\dfrac{7}{6}=\dfrac{17}{3}.\dfrac{7}{6}=\dfrac{119}{18}\)

c: Ta có: \(\dfrac{1}{3}-\dfrac{7}{8}x=\dfrac{1}{4}\)

\(\Leftrightarrow x\cdot\dfrac{7}{8}=\dfrac{1}{12}\)

\(\Leftrightarrow x=\dfrac{1}{12}\cdot\dfrac{8}{7}=\dfrac{2}{21}\)

d: Ta có: \(\dfrac{3}{2}x+\dfrac{1}{7}=\dfrac{7}{8}\cdot\dfrac{64}{49}\)

\(\Leftrightarrow x\cdot\dfrac{3}{2}=1\)

hay \(x=\dfrac{2}{3}\)