A. \(\frac{4}{5}\times\frac{8}{3}\times\frac{x}{7}=\frac{96}{105}\)

=\(\frac{4}{5}\times\left(\frac{8}{3}\times\frac{x}{7}\right)=\frac{96}{105}\)

= \(\frac{8}{3}\times\frac{x}{7}=\frac{96}{105}\div\frac{4}{5}\)

= \(\frac{8}{3}\times\frac{x}{7}=\frac{480}{420}=\frac{8}{7}\)

=\(\frac{x}{7}=\frac{8}{7}\div\frac{8}{3}\)

= \(X=\frac{24}{56}=\frac{3}{7}\)

\(X=3\)

@Moon

a)\(\frac{4}{5}\cdot\frac{8}{3}\cdot\frac{x}{7}=\frac{96}{105}\)

\(\frac{4}{5}\cdot\frac{8}{3}\cdot\frac{x}{7}=\frac{32}{35}\)

\(\frac{4\cdot8\cdot x}{5\cdot3\cdot7}=\frac{32}{35}\)

\(\frac{32\cdot x}{105}=\frac{32}{35}\)

\(\Rightarrow32\cdot x\cdot35=32\cdot105\)( chỗ này là nhân tích chéo nha )

\(\Rightarrow x\cdot35=105\)

\(x=105:35\)

\(x=3\)Vậy x=3

b)\(\frac{7}{4}\cdot\frac{3}{x}\cdot\frac{11}{5}=\frac{231}{200}\)

\(\frac{7\cdot3\cdot11}{4\cdot x\cdot5}=\frac{231}{200}\)

\(\frac{231}{20\cdot x}=\frac{231}{200}\)

\(\Rightarrow20\cdot x=200\)

\(x=200:20\)

\(x=10\)Vậy x=10

a) \(\frac{4}{5}\times\frac{8}{3}\times\frac{x}{7}=\frac{96}{105}\)

\(\frac{32}{15}\times\frac{x}{7}=\frac{32}{35}\)

\(\frac{x}{7}=\frac{32}{35}:\frac{32}{15}\)

\(\frac{x}{7}=\frac{3}{7}\)

\(\Rightarrow x=3\)

b) \(\frac{7}{4}\times\frac{3}{x}\times\frac{11}{5}=\frac{231}{200}\)

\(\frac{7}{4}\times\frac{11}{5}\times\frac{3}{x}=\frac{231}{200}\)

\(\frac{77}{20}\times\frac{3}{x}=\frac{231}{200}\)

\(\frac{3}{x}=\frac{231}{200}:\frac{77}{20}\)

\(\frac{3}{x}=\frac{3}{10}\)

\(\Rightarrow x=10\)

CHÚC BẠN HỌC TỐT!!!!!!!!!!

a) 32 : (3.x - 2) = 8

3x - 2 = 32 : 8

3x - 2 = 4

3x = 4 + 2

3x = 6

x = 6 : 3

x = 2

b) 75 : (x - 18) = 25

x - 18 = 75 : 25

x - 18 = 3

x = 3 + 18

x = 21

c) (15 - 6.x) . 243 = 729

15 - 6x = 729 : 243

15 - 6x = 3

6x = 15 - 3

6x = 12

x = 12 : 6

x = 2

d) 4.(x - 12) + 9 = 17

4(x - 12) = 17 - 9

4(x - 12) = 8

x - 12 = 8 : 4

x - 12 = 2

x = 2 + 12

x = 14

e) 20 - 2.(x + 4) = 4

2(x + 4) = 20 - 4

2(x + 4) = 16

x + 4 = 16 : 2

x + 4 = 8

x = 8 : 2

x = 4

`32: ( 3xx x -2)=8`

`3xx x-2=32:8`

`3xx x-2=4`

`3 xx x=4+2`

`3xx x=6`

`x=6:3`

`x=2`

__

`75 : (x-18) =25`

`x-18=75:25`

`x-18= 3`

`x=3+18`

`x=21`

__

`(15-6 xx x ) xx 243 =729`

`15-6 xx x = 729 : 243`

`15-6 xx x = 3`

`6 xx x=15-3`

`6 xx x=12`

`x=12:6`

`x=2`

__

`4 xx (x-12)+9=17`

`4 xx (x-12)=17-9`

`4 xx (x-12)= 8`

`x-12=8:4`

`x-12=2`

`x=2+12`

`x=14`

__

`20-2xx(x+4)=4`

`2xx(x+4)=20-4`

`2xx(x+4)=16`

`x+4=16:2`

`x+4=8`

`x=8-4`

`x=4`

a)4/3:x=-4/7                         b)5/3.x=7/12

⇒x=-16/21                             ⇒x=7/20

a. \(\dfrac{5}{7}+\dfrac{4}{3}:x=\dfrac{1}{7}\)

<=> \(\dfrac{5}{7}+\dfrac{4}{3}.\dfrac{1}{x}=\dfrac{1}{7}\)

<=> \(\dfrac{5}{7}+\dfrac{4}{3x}=\dfrac{1}{7}\)         ĐKXĐ: x \(\ne\) 0

<=> \(\dfrac{15x}{21x}+\dfrac{28}{21x}=\dfrac{3x}{21x}\)

<=> 15x + 28 = 3x

<=> 15x - 3x = -28

<=> 12x = -28

<=> x = \(\dfrac{-28}{12}=-\dfrac{7}{3}\)

b. \(\dfrac{5}{3}x.\dfrac{-1}{4}=\dfrac{2}{6}\)

<=> \(\dfrac{-5x}{12}=\dfrac{2}{6}\)

<=> -5x . 6 = 12 . 2

<=> -30x = 24

<=> x = \(-\dfrac{4}{5}\)

a) x + \(\dfrac{3}{4}\) = \(\dfrac{5}{3}\)

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

    x = \(\dfrac{20}{12}\) - \(\dfrac{9}{12}\)  

    x =  \(\dfrac{11}{12}\) 

b) x - \(\dfrac{2}{3}\) = \(\dfrac{7}{2}\)

    x = \(\dfrac{7}{2}\) + \(\dfrac{2}{3}\) 

    x = \(\dfrac{21}{6}\) + \(\dfrac{4}{6}\) 

    x = \(\dfrac{25}{6}\)

nhanh lên nhé 

\(a,x-\dfrac{1}{4}=\dfrac{7}{2}.\dfrac{-3}{5}\\ \Rightarrow x-\dfrac{1}{4}=\dfrac{-21}{10}\\ \Rightarrow x=\dfrac{-21}{10}+\dfrac{1}{4}\\ \Rightarrow x=\dfrac{-37}{20}\\ b,\dfrac{x}{134}=\dfrac{9}{7}.\dfrac{5}{-11}\\ \Rightarrow\dfrac{x}{134}=\dfrac{-45}{77}\\ \Rightarrow x=\dfrac{-45}{77}.134\\ \Rightarrow x=\dfrac{-6030}{77}\)

\(x-\dfrac{1}{4}=\dfrac{7}{2}\cdot\dfrac{-3}{5}\)

\(x-\dfrac{1}{4}=\dfrac{-21}{10}\)

\(x=\dfrac{-21}{10}+\dfrac{1}{4}\)

\(x=\dfrac{-37}{20}\)

b ) \(\dfrac{x}{134}=\dfrac{9}{7}\cdot\dfrac{5}{-11}\)

      \(\dfrac{x}{134}=\dfrac{9}{7}\cdot\dfrac{-5}{11}\)

       \(\dfrac{x}{134}=\dfrac{-45}{77}\)

       \(x=\dfrac{-45}{77}\cdot134\)

       \(x=-\dfrac{6034}{77}\)

a) \(\left(3x+5\right)\left(7-2x\right)+6x\left(x+4\right)=0\)

\(\Leftrightarrow21x-6x^2+35-10x+6x^2+24x=0\)

\(\Leftrightarrow35x=-35\Leftrightarrow x=-1\)

b) \(x^3-25x=0\)

\(\Leftrightarrow x\left(x^2-25\right)=0\)

\(\Leftrightarrow x\left(x-5\right)\left(x+5\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=5\\x=-5\end{matrix}\right.\)

a: Ta có: \(\left(3x+5\right)\left(7-2x\right)+6x\left(x+4\right)=0\)

\(\Leftrightarrow21x-6x^2+35-10x+6x^2+24x=0\)

\(\Leftrightarrow x=1\)

b: Ta có: \(x^3-25x=0\)

\(\Leftrightarrow x\left(x-5\right)\left(x+5\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=5\\x=-5\end{matrix}\right.\)