Đáp án:
Giải thích các bước giải:
1) 2(x+1) + x + 1 = 0 2) x(x-1)+x -1 = 0
2x + 2 + x + 1 = 0 x^2 - x +x -1 = 0
3x + 3 = 0 X^2 = 1
3x = -3 X^2 = 1^2
x=-1 x = 1
3) 2x(x-2)+2x-4=0 4) 3(x-1)-x-1= 0
2x^2 -4x+ 2x - 4 = 0 3x - 3 -x - 1 = 0
2x ( x -2 ) + 2(x-2)=0 2x - 4 = 0
(x-2)(2x+2)= 0 x = 2
=>| x-2 = 0 => x =2
| 2x + 2 = 0 => x= -1
5) 3x( 2x - 1) - 2x +1 =0 6) x -3 + 3x(x-3)=0
6x^2 - 3x - 2x +1 = 0 x - 3 + 3x^2 - 9x = 0
3x ( 2x - 1) - ( 2x - 1 ) = 0 3x^2 + x - 9x - 3 =0
(2x - 1)(3x - 1 ) = 0 x ( 3x + 1 ) - 3( 3x + 1 ) = 0
=> | x = 1/2 (3x + 1 ) ( x-3) = 0
| x = 1/3 => | x = -1/3
| x = 3
