`1)`

`3x(4x-1)-(2x+1)(6x+5)=0`

`\to (12x^2-3x)-(12x^2+16x+5)=0`

`\to 12x^2-3x-12x^2-16x-5=0`

`\to (12x^2-12x^2)-(3x+16x)-5=0`

`\to -19x-5=0`

`\to -19x=5`

`\to x=-5/19`

Vậy `x=-5/19`

`2)`

`(x+3)(2x-1)-(x-4)(2x+1)=10`

`\to (2x^2+5x-3)-(2x^2-7x-4)=10`

`\to 2x^2+5x-3-2x^2+7x+4=10`

`\to (2x^2-2x^2)+(5x+7x)+(4-3)=10`

`\to 12x+1=10`

`\to 12x=9`

`\to x=3/4`

Vậy `x=3/4`

`3)`

`(3x+4)(2x-1)+6x(1-x)=0`

`\to (6x^2+5x-4)+(6x-6x^2)=0`

`\to 6x^2+5x-4+6x-6x^2=0`

`\to (6x^2-6x^2)+(5x+6x)-4=0`

`\to 11x-4=0`

`\to 11x=4`

`\to x=4/11`

Vậy `x=4/11`

`4)`

`2x(x^2-1)+x(1-3x-2x^2)=-x-27`

`\to (2x^3-2x)+(-2x^3-3x^2+x)=-x-27`

`\to 2x^3-2x^3-3x^2-2x+x+x+27=0`

`\to (2x^3-2x^3)-3x^2+(x+x-2x)+27=0`

`\to -3x^2+27=0`

`\to -3x^2=-27`

`\to x^2=9`

`\to x^2=3^2`

`\to` \(\left[ \begin{array}{l}x=3\\x=-3\end{array} \right.\) 

Vậy `x\in{-3;3}`

`#Sad`

`1,`

`3x(4x-1) - (2x+1)(5+6x) = 0`

`⇔12x^2-3x-10x-12x^2-5-6x = 0`

`⇔(12x^2-12x^2)+(-3x-10x-6x)-5 = 0`

`⇔-19x = 5`

`⇔x = -5/(19)`

`\text{Vậy}` `x= -5/(19)`

`2,`

`(x+3)(2x-1)-(x-4)(2x+1) = 10`

`⇔2x^2-x+6x-3-2x^2-x+8x+4 = 10`

`⇔(2x^2-2x^2)+(-x+6x-x+8x)+(-3+4) = 10`

`⇔12x+1 = 10`

`⇔12x = 9`

`⇔x = 3/4`

`\text{Vậy}` `x=3/4`

`3,`

`(3x+4)(2x-1)+6x(1-x) = 0`

`⇔6x^2-3x+8x-4+6x-6x^2 = 0`

`⇔(6x^2-6x^2)+(-3x+8x+6x)-4 = 0`

`⇔11x = 4`

`⇔x = 4/(11)`

`\text{Vậy}` `x=4/(11)`

`4,`

`2x(x^2-1)+x(1-3x-2x^2) = -x-27`

`⇔2x^3-2x+x-3x^2-2x^3 = -x-27`

`⇔(2x^2-2x^3)-3x^2+(-2x+x) = -x-27`

`⇔-3x^2-x+x+27 = 0`

`⇔-3x^2+27 = 0`

`⇔-3x^2 =-27`

`⇔x^2 = 9`

`⇔`\(\left[ \begin{array}{l}x=3\\x=-3\end{array} \right.\) 

`\text{Vậy}` `x=3` `\text{hoặc}` `x=-3`

`\text{·Hướng dẫn:}`

`\text{→Khai triển phép nhân}`

`\text{→Rút gọn}`

`\text{→Tìm x}`