1. 4x-12=0

<=>4x=12

<=>x=3

2.  x.(x+1)-(x+2)(x+3)=7

<=>x²+x-x²-3x-2x-6=7

<=>x²-x²+x-2x-3x=7+6

<=>-4x=13

<=>x=\(-\dfrac{13}{4}\)

3.   7+2x=22-3x

<=>2x+3x=22-7

<=>5x=15

<=>x=3

4.  (x-1)-(2x-1)=9-x

<=>x-1-2x+1=9-x

<=>x-2x+x=9+1-1

<=>0x=9

vô nghiệm

bạn đăng tách cho mn cùng giúp nhé 

Bài 1 : 

a, \(\Leftrightarrow11-x=12-8x\Leftrightarrow7x=1\Leftrightarrow x=\dfrac{1}{7}\)

b, \(\Leftrightarrow2x\left(x^2+4x+4\right)-8x^2=2\left(x^3-8\right)\)

\(\Leftrightarrow2x^3+8x^2+8x-8x^2=2x^3-16\Leftrightarrow x=-2\)

c, \(\Leftrightarrow3-2x=-x-4\Leftrightarrow x=7\)

d, \(\Leftrightarrow x^3-6x^2+12x-8+9x^2-1=x^3+3x^2+3x+1\)

\(\Leftrightarrow3x^2+12x-9=3x^2+3x+1\Leftrightarrow x=\dfrac{10}{9}\)

e, \(\Leftrightarrow2x^2-x-3=2x^2+9x-5\Leftrightarrow x=5\)

f, \(\Leftrightarrow x^3-3x^2+3x-1-x^3-2x^2-x=10x-5x^2-11x-22\)

\(\Leftrightarrow-5x^2+2x-1=-5x^2-x-22\Leftrightarrow3x=-21\Leftrightarrow x=-7\)

h) \(PT\Leftrightarrow x^2+4x-3x-12-6x+4=x^2-8x+16\)

\(\Leftrightarrow3x=24\)

\(\Leftrightarrow x=8\)

Vậy: \(S=\left\{8\right\}\)

j) \(PT\Leftrightarrow x^3-x^2+x+x^2-x+1-2x=x^3-x\)

\(\Leftrightarrow x=1\)

Vậy: \(S=\left\{1\right\}\)

\(a,\dfrac{x-3}{x}=\dfrac{x-3}{x+3}\)\(\left(đk:x\ne0,-3\right)\)

\(\Leftrightarrow\dfrac{x-3}{x}-\dfrac{x-3}{x+3}=0\)

\(\Leftrightarrow\dfrac{\left(x-3\right)\left(x+3\right)-x\left(x-3\right)}{x\left(x+3\right)}=0\)

\(\Leftrightarrow x^2-9-x^2+3x=0\)

\(\Leftrightarrow3x-9=0\)

\(\Leftrightarrow3x=9\)

\(\Leftrightarrow x=3\left(n\right)\)

Vậy \(S=\left\{3\right\}\)

\(b,\dfrac{4x-3}{4}>\dfrac{3x-5}{3}-\dfrac{2x-7}{12}\)

\(\Leftrightarrow\dfrac{4x-3}{4}-\dfrac{3x-5}{3}+\dfrac{2x-7}{12}>0\)

\(\Leftrightarrow\dfrac{3\left(4x-3\right)-4\left(3x-5\right)+2x-7}{12}>0\)

\(\Leftrightarrow12x-9-12x+20+2x-7>0\)

\(\Leftrightarrow2x+4>0\)

\(\Leftrightarrow2x>-4\)

\(\Leftrightarrow x>-2\)

giúp mik với

a: =>-x+2x=3-7

=>x=-4

b: =>6x+2+2x-5=0

=>8x-3=0

hay x=3/8

c: =>5x+2x-2-4x-7=0

=>3x-9=0

hay x=3

d: =>10x²-10x²-15x=15

=>-15x=15

hay x=-1

Bài 1:

a) (5x-4)(4x+6)=0

\(\Leftrightarrow\orbr{\begin{cases}5x-4=0\\4x+6=0\end{cases}\Leftrightarrow\orbr{\begin{cases}5x=4\\4x=-6\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=\frac{4}{5}\\y=\frac{-3}{2}\end{cases}}}\)

b) (x-5)(3-2x)(3x+4)=0

<=> x-5=0 hoặc 3-2x=0 hoặc 3x+4=0

<=> x=5 hoặc x=\(\frac{3}{2}\)hoặc x=\(\frac{-4}{3}\)

c) (2x+1)(x²+2)=0

=> 2x+1=0 (vì x²+2>0)

=> x=\(\frac{-1}{2}\)

bài 1: 

a) (5x - 4)(4x + 6) = 0

<=> 5x - 4 = 0 hoặc 4x + 6 = 0

<=> 5x = 0 + 4 hoặc 4x = 0 - 6

<=> 5x = 4 hoặc 4x = -6

<=> x = 4/5 hoặc x = -6/4 = -3/2

b) (x - 5)(3 - 2x)(3x + 4) = 0

<=> x - 5 = 0 hoặc 3 - 2x = 0 hoặc 3x + 4 = 0

<=> x = 0 + 5 hoặc -2x = 0 - 3 hoặc 3x = 0 - 4

<=> x = 5 hoặc -2x = -3 hoặc 3x = -4

<=> x = 5 hoặc x = 3/2 hoặc x = 4/3

c) (2x + 1)(x^2 + 2) = 0

vì x^2 + 2 > 0 nên:

<=> 2x + 1 = 0

<=> 2x = 0 - 1

<=> 2x = -1

<=> x = -1/2

bài 2: 

a) (2x + 7)^2 = 9(x + 2)^2

<=> 4x^2 + 28x + 49 = 9x^2 + 36x + 36

<=> 4x^2 + 28x + 49 - 9x^2 - 36x - 36 = 0

<=> -5x^2 - 8x + 13 = 0

<=> (-5x - 13)(x - 1) = 0

<=> 5x + 13 = 0 hoặc x - 1 = 0

<=> 5x = 0 - 13 hoặc x = 0 + 1

<=> 5x = -13 hoặc x = 1

<=> x = -13/5 hoặc x = 1

b) (x^2 - 1)(x + 2)(x - 3) = (x - 1)(x^2 - 4)(x + 5)

<=> x^4 - x^3 - 7x^2 + x + 6 = x^4 + 4x^3 - 9x^2 - 16x + 20

<=> x^4 - x^3 - 7x^2 + x + 6 - x^4 - 4x^3 + 9x^2 + 16x - 20 = 0

<=> -5x^3 - 2x^2 + 17x - 14 = 0

<=> (-x + 1)(x + 2)(5x - 7) = 0

<=> x - 1 = 0 hoặc x + 2 = 0 hoặc 5x - 7 = 0

<=> x = 0 + 1 hoặc x = 0 - 2 hoặc 5x = 0 + 7

<=> x = 1 hoặc x = -2 hoặc 5x = 7

<=> x = 1 hoặc x = -2 hoặc x = 7/5

\(\left(5x-4\right)\left(4x+6\right)=0\)

\(< =>\orbr{\begin{cases}5x-4=0\\4x+6=0\end{cases}}\)

\(< =>\orbr{\begin{cases}5x=4\\4x=-6\end{cases}}\)

\(< =>\orbr{\begin{cases}x=\frac{4}{5}\\x=-\frac{6}{4}=-\frac{3}{2}\end{cases}}\)

a) \(3x-2=2x-3\)

\(\Leftrightarrow x+1=0\)

\(\Leftrightarrow x=-1\)

b) \(3-4y+24+6y=y+27+3y\)

\(\Leftrightarrow-2y=0\Leftrightarrow y=0\)

c) \(7-2x=22-3x\)

\(\Leftrightarrow x-15=0\)

\(\Leftrightarrow x=15\)

d) \(8x-3=5x+12\)

\(\Leftrightarrow3x-15=0\Leftrightarrow x=5\)

e) \(x-12+4x=25+2x-1\)

\(\Leftrightarrow3x-36=0\)

\(\Leftrightarrow x=12\)

f) \(x+2x+3x-19=3x+5\)

\(\Leftrightarrow3x-24=0\)

\(\Leftrightarrow x=8\)

a) 3x - 2 = 2x-3

<=> 3x-2 -2x +3 = 0

<=> x +1 = 0

<=> x = -1

c) 3 - 4y+24+6y=y+27+3y

<=> 3 - 4y+24+6y - y - 27 - 3y = 0

<=> -2y =0

<=> y = 0

b,7-2x = 22 - 3x

<=> 7-2x -22 +3x = 0

<=> -15 +x = 0

<=> x = 15

d) x-12+4x = 25+2x-1

<=> x-12+4x -25-2x+1=0

<=> 3x -36 = 0

<=> 3x = 36

<=> x = 12

còn câu e bạn tự làm nha

\(a,3x-2=2x-3\)

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

\(x=-1\)

Vậy pt cs nghiệm là  { -1 }

\(b,7-2x=22-3x\)

\(-2x+3x=22-7\)

\(x=15\)

Vậy pt cs nghiệm là { 15 }

bn lm nốt nha ... 

a) 3x - 2 = 2x-3

<=> 3x-2 -2x +3 = 0

<=> x +1 = 0

<=> x = -1

b) 3 - 4y+24+6y=y+27+3y

<=> 3 - 4y+24+6y - y - 27 - 3y = 0

<=> -2y =0

<=> y = 0

c)7-2x = 22 - 3x

<=> 7-2x -22 +3x = 0

<=> -15 +x = 0

<=> x = 15

d) x-12+4x = 25+2x-1

<=> x-12+4x -25-2x+1=0

<=> 3x -36 = 0

<=> 3x = 36

<=> x = 12