\(7x.\left(2+x\right)-7x.\left(x+3\right)=14\)

           \(7x.\left(2+x-x-3\right)=14\)

                                \(7x.\left(-1\right)=14\)

                                             \(7x=14:\left(-1\right)\)

                                              \(7x=-14\)

                                                \(x=\left(-14\right):7\)

                                                \(x=-2\)

7x.( 2 + x ) - 7x( x + 3 ) = 14

<=> 7x( 2 + x - x - 3 ) = 14

<=> 7x.(-1) = 14

<=> -7x = 14

<=> x = -2

        7x(2+x )- 7x (x+3) = 14 
<=>  14x + 7x² - 7x² - 21x = 14

<=>  -7x = 14

<=>  x = -2
 

x có phải là dấu nhân hay là số

7x.(2+x)-7x.(x+3)=14

7x.[(2+x)-(3+x)]=14

7x.[2+x-3-x]=14

7x.(-1)         =14

7x                 =14:(-1)

7x                 =-14

x                   =-14:7

x                   =-2

Chúc bn học tốt

\(7x\left(2+x\right)-7x\left(x+3\right)=14\)

\(\Leftrightarrow14x+7x^2-7x^2-21x=14\)

\(\Leftrightarrow-7x=14\)\(\Leftrightarrow x=-2\)

Vậy \(x=-2\)

7x.(2+x)-7x.(x+3)=14

7x.(2+x-x-3)=14

7x.(-1)=14

7x=14:(-1)

7x=-14

x=-14:7

x=2

Vậy x=2

tk nha!

Tìm x €Z biết

4.(2x+9)+(-8.x+3) -(x-13)=0

7x ( 2 + x - x - 3 ) = 14

-7x = 14

x = -2 

\(7x\left(2+x\right)-7x\left(x+3\right)=14\)

\(\Rightarrow7x\left[\left(2+x\right)-\left(x+3\right)\right]=14\)

\(\Rightarrow7x\left[2+x-x-3\right]=14\)

\(\Rightarrow7x.\left(-1\right)=14\)

\(\Rightarrow-7x=14\)

\(\Rightarrow x=14:-7\)

\(\Rightarrow x=-2\)

Vậy x = -2

_Chúc bạn học tốt_

   + -2X-12+6X-60=8

<=>4X=80]

<=> X = 20

         V.....

   + -8X-36 +8X -3 - X - 13 =0

 <=> -X = 52

 <=> X = -52

           V.....

   + 14X +7\(X^2\)-7\(X^2\)-21X=14

    <=> -7X  =14

     <=> X= -2 

              V .......

a: \(x^2\left(x-3\right)-4x+12\)

\(=x^2\left(x-3\right)-4\left(x-3\right)\)

\(=\left(x-3\right)\left(x-2\right)\left(x+2\right)\)

b: \(2a\left(x+y\right)+x+y=\left(x+y\right)\left(2a+1\right)\)

c: \(6x^2-12x-7x+14\)

\(=6x\left(x-2\right)-7\left(x-2\right)\)

\(=\left(x-2\right)\left(6x-7\right)\)

a.

-2 (x+6)+6 (x-10)=8

-2x -12 +6x -60 =8

4x -72 =8

4x = -64

  x= -16

b.

7x (2+x) -7x (x+3) =14

7x [ (2+x)-(x+3) ] =14

7x (2+x-x-3) =14

-7x =14

x= -2

a: \(\dfrac{x^2-5x+6}{x^2+7x+12}:\dfrac{x^2-4x+4}{x^2+3x}\)

\(=\dfrac{\left(x-2\right)\left(x-3\right)}{\left(x+3\right)\left(x+4\right)}\cdot\dfrac{x\left(x+3\right)}{\left(x-2\right)^2}\)

\(=\dfrac{x\left(x-3\right)}{\left(x-2\right)\left(x+4\right)}\)

b: \(\dfrac{x^2+2x-3}{x^2+3x-10}:\dfrac{x^2+7x+12}{x^2-9x+14}\)

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

\(=\dfrac{\left(x-1\right)\left(x-7\right)}{\left(x+5\right)\left(x+4\right)}\)