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

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

         \(x\)    = \(\dfrac{1}{21}\)  - \(\dfrac{1}{5}\) 

          \(x\) = - \(\dfrac{16}{105}\) 

-9/10x(5/14+1/7)+1/10x-9/2

=-9/10x7/14+1/10x-9/2

-9/10x1/2+1/10x-9/2

=-9/20+--9/20

=-18/20=-9/10

Đề kiểu j v

troll ng à

\(2x+10⋮x+1\)

\(\Rightarrow2x+2+8⋮x+1\)

\(\Rightarrow2\left(x+1\right)+8⋮x+1\)

\(\Rightarrow x+1\inƯ\left(8\right)=\left\{\pm1;\pm2;\pm4;\pm8\right\}\)

\(x\in\left\{0;1;-2;\pm3;-5;7;-9\right\}\)

\(2x+10⋮x-1\)

\(\Rightarrow2x-2+12⋮x-1\)

\(\Rightarrow2\left(x-1\right)+12⋮x-1\)

\(\Rightarrow x-1\inƯ\left(12\right)=\left\{\pm1;\pm2;\pm3;\pm4;\pm6;\pm12\right\}\)

x - 1 = 1 => x = 2

x -1 = -1 => x = 0 

... tg tự 

12va 1

12 và 1

a) -10 - (x - 5) + (3 - x) = -8

=> -10 - x + 5 + 3 -x = -8

=> -2x - 2 = -8

=> -2x = -6

=> x = -6/-2 = 3

b) 10 + 3(x - 1) = 10 + 6x

=> 10 + 3x - 3 = 10 + 6x

=> 3x - 6x = 10 - 7

=> -3x = 3

=> x = 3/-3 = -1

c) (x + 1)(x  - 2) = 0

=> \(\orbr{\begin{cases}x+1=0\\x-2=0\end{cases}}\)

=> \(\orbr{\begin{cases}x=-1\\x=2\end{cases}}\)