a/. X  x  8 = 2864   

             X = 2864 : 8   

             X = 358

b/. X  :  5 = 1232

            X = 1232 x 5

             X = 6160

a/. X  x  8 = 2864  

             X = 2864 : 8        

             X = 358  

b/. X  :  5 = 1232  

            X = 1232 x 5     

            X = 6160 

a)

`x/(-8)=5/4`

`=>x*4=5*(-8)`

`=>4x=-40`

`=>x=-40:4`

`=>x=-10`

b)

`(-13)/x=(-65)/10`

`=>(-13)/x=(-13)/2`

`=>x=2`

c)

`(-6)/5=(-12)/x`

`<=>(-12)/10=(-12)/x`

`<=>x=10`

d)

`(x-2)/2=8/(x-2)`

`=>(x-2)(x-2)=8*2`

`=>(x-2)^2=16`

`=>x-2=4` hoặc`x-2=-4`

`=>x=4+2` hoặc `x=-4+2`

`=>x=6` hoặc `x=-2`

`x/(-8) = 5/4`

`=> 4x=5.(-8)`

`=>4x=-40`

`=>x=-40:4`

`=>x=-10`

__

`-13/x =-65/10`

`=> -65x=-130`

`=>x=-130:(-65)`

`=>x= 2`

__

`-6/5 =-12/x`

`=> -6x=-12.5`

`=> -6x= -60`

`=>x=-60:(-6)`

`=>x=10`

__

`(x-2)/2 = 8/(x-2)`

`=>(x-2)^2=2.8`

`=>(x-2)^2=16`

`=> (x-2)^2=+-4^2`

\(\Rightarrow\left[{}\begin{matrix}x-2=4\\x-2=-4\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=6\\x=-2\end{matrix}\right.\)

a. \(\dfrac{x}{5}=\dfrac{8}{10}\)

\(\Rightarrow10x=8.5\)

\(\Rightarrow10x=40\)

\(\Rightarrow x=\dfrac{40}{10}=4\)

b. \(\dfrac{9}{x}=\dfrac{90}{100}\)

\(\Rightarrow9.100=90x\)

\(\Rightarrow900=90x\)

\(\Rightarrow x=\dfrac{900}{90}=10\)

c. \(17+\dfrac{x}{35}=\dfrac{5}{7}\)

\(\Rightarrow\dfrac{595+x}{35}=\dfrac{25}{35}\)

\(\Rightarrow595+x=25\)

\(\Rightarrow x=25-595=-570\)

d. \(x:\dfrac{5}{27}=\dfrac{2}{9}\)

\(\Rightarrow\dfrac{27x:5}{27}=\dfrac{6}{27}\)

\(\Rightarrow27x:5=6\)

\(\Rightarrow27x=5.6\)

\(\Rightarrow27x=30\)

\(\Rightarrow x=\dfrac{30}{27}=\dfrac{10}{9}\approx1,11\)

a: x=-5/11+2/11=-3/11

b: =>x=-3/24+20/24+1/24=18/24=3/4

c: =>5/8-x=1/9+5/4=4/36+45/36=49/36

=>x=5/8-49/36=-53/72

d: =>2/3-x=1/3

=>x=1/3

e: =>1/5:x=12/35

=>x=7/12

\(a,x=\dfrac{1}{2}-\dfrac{2}{5}\)

\(x=\dfrac{1}{10}\)

\(b,x+\dfrac{3}{7}=\dfrac{7}{10}\)

\(x=\dfrac{7}{10}-\dfrac{3}{7}\)

\(x=\dfrac{19}{70}\)

\(c,19-x=\dfrac{17}{20}\)

\(x=19-\dfrac{17}{20}\)

\(x=\dfrac{363}{20}\)

a,1/10

b,19/70

c,18/4

x=36320

a: x=9/2-3/7=57/14

b: =>x=7/5x5/7=1

c: =>x=11/3:3/8=11/3x8/3=88/9

a : x = \(\dfrac{9}{2}\) - \(\dfrac{3}{7}\) = \(\dfrac{57}{14}\)

b : = > x = \(\dfrac{7}{5}\) x\(\dfrac{5}{7}\) = 1

 c : = >  \(\dfrac{11}{3}\) : \(\dfrac{3}{8}\) = \(\dfrac{11}{3}\) x \(\dfrac{8}{3}\) = \(\dfrac{88}{9}\)

\(a,\Leftrightarrow\left[{}\begin{matrix}x-8=0\\x^3+8=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=8\\x^3=-8\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=8\\x=-2\end{matrix}\right.\\ b,\Leftrightarrow4x-3-x-5=30-3x\\ \Leftrightarrow4x-x+3x=30+5+3\\ \Leftrightarrow6x=38\\ \Leftrightarrow x=\dfrac{19}{3}\)

a) \(\dfrac{8}{x}+\dfrac{1}{5}=\dfrac{2}{5}+\dfrac{1}{3}=\dfrac{11}{15}\)

\(\dfrac{8}{x}=\dfrac{11}{15}-\dfrac{1}{5}=\dfrac{8}{15}\)

\(x=\dfrac{8\times15}{8}=15\)

B) \(\left(x-\dfrac{3}{5}\right)=\dfrac{5}{8}\times\dfrac{1}{5}=\dfrac{1}{8}\)

\(x=\dfrac{1}{8}+\dfrac{3}{5}=\dfrac{29}{40}\)