Đáp án+Giải thích các bước giải:

`a) 2x(2 - 8x) - 12x(1 - 2x) = 6`

`4x - 16x^2 - 12x + 24x^2 - 6 = 0`

`8x^2 - 8x - 6 = 0`

`8x^2 - 4x + 12x - 6 = 0`

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

$\left[\begin{matrix} 4x + 6 = 0\\ 2x-1=0\end{matrix}\right.$

$\left[\begin{matrix} 4x = -6\\ 2x=1\end{matrix}\right.$

$\left[\begin{matrix} x=\dfrac{-3}{2}\\ x=\dfrac{1}{2}\end{matrix}\right.$

Vậy ...

`b) (2x + 1)(2x - 3) - (4x + 1)(x + 2) = 8`

`4x^2 - 4x - 3 - 4x^2 - 9x - 2 = 8`

`-13x - 5 = 8`

`-13x = 13`

`x = -1`

Vậy ...

`c) 2x (x - 5) - x(3 + 2x) = 26`

`2x^2 - 10x - 3x - 2x^2 = 26`

`-13x = 26`

`x = -2`

Vậy ...

`d) 2x(5 - 3x) + 2x(3x - 5) - 3x = 3`

`2x(5 - 3x) - 2x(5 - 3x) - 3x = 3`

`0 - 3x = 3`

`-3x = 3`

`x = -1`

Vậy ...