a) \(\left(x+3\right)\left(2x-1\right)-\left(x-3\right)\left(x+1\right)=0\)

\(\Leftrightarrow2x^2+5x-3-x^2+2x+3=0\)

\(\Leftrightarrow x^2+7x=0\Leftrightarrow x\left(x+7\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-7\end{matrix}\right.\)

b) \(\left(x+4\right)\left(2x-3\right)-3\left(x-2\right)\left(x+2\right)=0\)

\(\Leftrightarrow2x^2+5x-12-3x^2+12=0\)

\(\Leftrightarrow x^2-5x=0\Leftrightarrow x\left(x-5\right)=0\)

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

<=> 2x^2 - 2.2x.1 + 1^2 - 3( x^2 + x - x -1 ) + (-x^2) + 2.-x.3 + 3^2 = 2x^2 + 20x + 17

<=> 2x^2 - 4x + 1 - 3x^2 - 3x + 3x + 3 + (-x^2) + (-6x) + 3^2 = 2x^2 + 20x + 17

<=> ___________________________________________- 2x^2 - 20x - 17

<=> -2x^2 - 10x- 13

<=> a = - 2 ; b = - 10 ; c = -13

cảm ơn bạn, bạn giúp mk cả câu b đc ko

Bài 1: 

a) Ta có: \(\dfrac{17}{6}-x\left(x-\dfrac{7}{6}\right)=\dfrac{7}{4}\)

\(\Leftrightarrow\dfrac{17}{6}-x^2+\dfrac{7}{6}x-\dfrac{7}{4}=0\)

\(\Leftrightarrow-x^2+\dfrac{7}{6}x+\dfrac{13}{12}=0\)

\(\Leftrightarrow-12x^2+14x+13=0\)

\(\Delta=14^2-4\cdot\left(-12\right)\cdot13=196+624=820\)

Vì Δ>0 nên phương trình có hai nghiệm phân biệt là:

\(\left\{{}\begin{matrix}x_1=\dfrac{14-2\sqrt{205}}{-24}=\dfrac{-7+\sqrt{205}}{12}\\x_2=\dfrac{14+2\sqrt{2015}}{-24}=\dfrac{-7-\sqrt{205}}{12}\end{matrix}\right.\)

b) Ta có: \(\dfrac{3}{35}-\left(\dfrac{3}{5}-x\right)=\dfrac{2}{7}\)

\(\Leftrightarrow\dfrac{3}{5}-x=\dfrac{3}{35}-\dfrac{10}{35}=\dfrac{-7}{35}=\dfrac{-1}{5}\)

hay \(x=\dfrac{3}{5}-\dfrac{-1}{5}=\dfrac{3}{5}+\dfrac{1}{5}=\dfrac{4}{5}\)

ai giúp mik vs

Bài 3: 

a) Ta có: \(2x-3=x+\dfrac{1}{2}\)

\(\Leftrightarrow2x-x=\dfrac{1}{2}+3\)

\(\Leftrightarrow x=\dfrac{7}{2}\)

b) Ta có: \(4x-\left(x+\dfrac{1}{2}\right)=2x-\left(\dfrac{1}{2}-5\right)\)

\(\Leftrightarrow3x-\dfrac{1}{2}-2x+\dfrac{1}{2}-5=0\)

\(\Leftrightarrow x=5\)

FGFGG

a)-2x - 3.(x - 17) = 34 - (-x + 25)

   - 2x - 3x + 51 = 34 + x - 25

   - 2x - 3x - x = -51 + 34 - 25

   - 6x             = - 42

       x              = 7

Vậy x = 7

 b)-2x-3.(x-17)=34-2(-x+25)

- 2x - 3x + 51 = 34 + 2x - 50

- 2x - 3x - 2x = - 51 + 34 - 50

         7x        =  - 67

           x        = \(-\frac{67}{7}\)

Vậy  \(x=-\frac{67}{7}\)

c)17x-(-16x-37)=2x +43

  17x + 16x + 37 = 2x + 43

  17x + 16x - 2x = -37 + 43

               31x     = 6

                   x      = \(\frac{6}{31}\) 

Vậy \(x=\frac{6}{31}\)

tìm x biết:

(3x-1) [- 1/2x+5]=0

1/4+1/3:(2x-1)=-5

[2x+3/5]² - 9/25=0

-5(x+1/5)-1/2(x-2/3)=3/2x - 5 /6

[x+1/2]x [2/3-2x]=0

17/2-|2x-3/4|=-7/4

2/3x-1/2x =5/12

(x+1/5)²+17/25=26/25

[x.44/7+3/7].11/5-3/7=-2

3[3x-1/2]+1/9=0

Toán lớp 6Tìm x

 Trả lời  Câu hỏi tương tự

Chưa có ai trả lời câu hỏi này,bạn hãy là người đâu tiên giúp nguyenvanhoang giải bài toán này !

3(3x-1/2)^3+1/9=0

a, => 3^2x = 3^4

=>2x=4

=>x=2

b,=>2x+3x-3=17

=>5x-3=17

=>5x=17+3=20

=>x=4

c,=>x+15=(2x+3).2 = 4x+6

=>4x+6-(x+15)=0

=>4x+6-x-15=0

=>3x-9=0

=>3x=9

=>x=3

k mk nha

a,x=2

b,

a) 3^2x = 81

     3^2x = 3^4

     2x     = 4

       x      = 4:2

       x = 2

b) 2x + 3 . (x - 1) = 17

     2x + 3x - 3.1 = 17

     (2+3)x - 3 = 17

     5x              = 17 + 3

     5x              = 20

       x              = 20:5

       x              = 4

c) (x + 15) : 2 = 2x + 3

(x+15).1/2 = 2x + 3

(1/2)x + (1/2).15 = 2x + 3

(1/2)x + 15/2 = 2x + 3

(1/2)x - 2x = 3 - (15/2)

(1/2 - 2)x = -9/2

(-3/2)x = -9/2

x = (-9/2):(-3/2)

x = 3

a)

 13/4+x=2

          x=2-13/4

         x=-5/4

b)

 2x.17/12=3/7

 2x          =3/7;17/12

 2x         =36/119

  x           =36/119 : 2

  x           =18/119

c)

 2x.17/12=19/7

 2x         =19/7:17/12

 2x         =228/119

   x         =228/119;2

   x         =114/119

d)

 1/2x + 5/6=-3

 1/2x         =-3-5/6

 1/2x         =-23/6

     x          =-23/6:1/2

    x          =-23/3

\(\Rightarrow x^3-3x^2+3x-1+8-x^3=17-3x^2-6x\\ \Rightarrow9x=10\Rightarrow x=\dfrac{10}{9}\)