a, \(-4x+5+2x-1=3\Leftrightarrow-2x=-1\Leftrightarrow x=\dfrac{1}{2}\)

b, \(-2x+2=2\Leftrightarrow x=0\)

c, \(-2x-6=-8\Leftrightarrow x=1\)

a) \(2.\left|5x-3\right|-2x=14\)

\(2\left|5x-3\right|=14+2x\)

\(\left|5x-3\right|=\frac{14+2x}{2}\)

\(\Rightarrow\orbr{\begin{cases}5x-3=\frac{-14-2x}{2}\\5x-3=\frac{14+2x}{2}\end{cases}}\)\(\Rightarrow\orbr{\begin{cases}\left(5x-3\right).2=-14-2x\\\left(5x-3\right).2=14+2x\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}10x-6+2x=-14\\10x-6-2x=14\end{cases}\Rightarrow\orbr{\begin{cases}12x=-14+6\\8x=14+6\end{cases}}}\Rightarrow\orbr{\begin{cases}12x=-8\\8x=20\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=\frac{-2}{3}\\x=2,5\end{cases}}\)

vậy \(\orbr{\begin{cases}x=\frac{-2}{3}\\x=2,5\end{cases}}\)

Những câu sau tương tự nhé. 

làm giúp đi

a ) 

\(5x\left(4x-5\right)-4x\left(5x-6\right)=30\)

\(\Rightarrow20x^2-25x-20x^2+24x=30\)

\(\Rightarrow-x=30\)

\(\Rightarrow x=-30\)

Vậy ...

b ) 

\(2x\left(6-3x\right)+3x\left(2x-5\right)=12\)

\(\Rightarrow12x-6x^2+6x^2-15x=12\)

\(\Rightarrow-3x=12\)

\(\Rightarrow x=-4\)

Vậy ...

a) \(5x\left(4x-5\right)-4x\left(5x-6\right)-30\)

\(\Rightarrow20x^2-25x-20x^2+24x=30\)

\(\Rightarrow-1x=30\)

\(\Rightarrow x=-30\)

Vậy x = -30

b) \(2x\left(6-3x\right)+3x\left(2x-5\right)=12\)

\(\Rightarrow12x-6x^2+6x^2-15x=12\)

\(\Rightarrow-3x=12\)

\(\Rightarrow x=-4\)

Vậy x = -4

cảm ơn các bạn nếu đc các bạn có thể trả lời hết số câu hỏi tớ vừa hỏi có đc ko ạ

3,26 + 4/5 =?

làm nhanh lên giúp mình nhé

3,26+4/5=3,26+0,8=3,34

K cho mình cái

\(2\left(5x-8\right)-3\left(4x-5\right)=4\left(3x-4\right)+11\)

\(\Leftrightarrow10x-16-12x+15=12x+16+11\)

\(\Leftrightarrow-2x-1=12x+27\Leftrightarrow-14x-28=0\Leftrightarrow x=-2\)

a)B=(3x.4x-11)+5x².(x-1)-4x.(3x+9)+x.5x-5x²

=12x²-11+5x³-5x²-12x²-36x+5x²-5x²

=5x³+(12x²-12x²+5x²-5x²-5x²)-36x-11

=5x³-5x²-36x-11

b)|x|=2=>x=2 hoặc x=-2

*)x=2 =>B=5.2³-5.2²-36.2-11=40-20-72-11=-63

*)x=-2 =>B=5.(-2)³-5.(-2)²-36.(-2)-11=-40-20+72-11=1

c)B=207

=>5x³-5x²-36x-11=207

<=>5x³-5x²-36x-218=0(bó tay)

 P= 3x ( 4x - 11 ) + 5x² ( x - 1 ) - 4x ( 3x + 9 ) + x ( 5x - 5x² )

\(P=12x^2-33x+5x^3-5x^2-12x^2-36x+5x^2-5x^3\)

\(P=-69x\)

b)\(TH1:x=2\). PT có dạng:

      \(-69x=-69.2=-138\)

\(TH2:x=-2\). PT có dạng
       \(-69x=-69.\left(-2\right)=138\)

c)Tại P=207 ta đc:

    \(-69x=207\Rightarrow x=-3\)

mơn bn nhé #Trịnh_Thành_Công

$ a/ 12x(x – 5) – 3x(4x - 10) = 120$

`<=>12x^2-60x-12x^2+30x=120`

`<=>-30x=120`

`<=>x=-4`

Vậy `x=-4`

$b/ 9x(x + 4) – 5x(3x + 2) = 112 - 2x(3x + 1)$

`<=>9x^2+36x-15x^2-10x=112-6x^2-2x`

`<=>-6x^2+26x=112-6x^2-2x`

`<=>28x=112`

`<=>x=4`

Vậy `x=4`

$c/ 3x(1 – x) - 5x(3x + 7) = 154 + 9x(5 – 2x)$

`<=>3x-3x^2-15x^2-35x=154+45x-18x^2`

`<=>-32x-18x^2=154+45x-18x^2`

`<=>77x=-154`

`<=>x=-2`

Vậy `x=-2`

giúp em thé các anh chi em trên thế giới

\(a,3x^2-3x\left(x-2\right)=36\\ \Leftrightarrow3x^2-3x^2+6x=36\\ \Leftrightarrow6x=36\\ \Leftrightarrow x=6\\ b,5x\left(4x^2-2x+1\right)-2x\left(10x^2-5x+2\right)=-36\\ \Leftrightarrow20x^3-10x^2+5x-20x^3+10x^2-4x+36=0\\ \Leftrightarrow\left(20x^3-20x^3\right)+\left(-10x^2+10x^2\right)+\left(5x-4x\right)=-36\\ \Leftrightarrow x=-36\)

=>(2x+3).(10x+2)=(5x+2).(4x+5)

=>(2x.10x)+(2x.2)+(3.10x)+(3.2)=(5x.4x)+(5x.5)+(2.4x)+(2.5)

=>20x²+4x+30x+6=20x²+25x+8x+10

=>20x²-20x²+4x-8x+30x-25x=10-6

=>0+4x-8x+30x-25x=4

=>-4x+30x-25x=4

=>26x-25x=4

=>x=4

B)=>(3x-1).(5x-34)=(40-5x).(25-3x)

=>15x²-102x-5x+34=1000-120x-125x+15x²

=>15x²-107x+34=1000-245x+15x²

=>15x²-15x²-107x+245x=1000-34

=>0-107x+245x=966

=>138x=966

=>x=7

A,=>(2x+3).(10x+2)=(5x+2).(4x+5)

=>(2x.10x)+(2x.2)+(3.10x)+(3.2)=(5x.4x)+(5x.5)+(2.4x)+(2.5)

=>20x2+4x+30x+6=20x2+25x+8x+10

=>20x2-20x2+4x-8x+30x-25x=10-6

=>0+4x-8x+30x-25x=4

=>-4x+30x-25x=4

=>26x-25x=4

=>x=4