Bài . Tìm giá trị của x biết: a. 3(2x – 3) + 2(2 – x) = -3 b. 2x(x2 – 2) + x2 (1 – 2x) – x2 = -12 c. 3x(2x + 3) – (2x + 5)(3x – 2) = 8 d. 4x(x -1) – 3

`a) 3(2x-3)+2(2-x)=-3`

`<=> 6x-9+4-2x=-3`

`<=> 4x-5=-3`

`<=> 4x=2`

`<=> x=1/2`

`b) 2x(x^2-2)+x^2(1-2x)-x^2=-12`

`<=> 2x^3-4x+x^2-2x^3-x^2=-12`

`<=> -4x=-12`

`<=> x=3`

`c) 3x(2x+3)-(2x+5)(3x-2)=8`

`<=> 6x^2+9x-(6x^2-4x+15x-10)=8`

`<=> 6x^2+9x-6x^2-11x+10=8`

`<=> -2x=-2`

`<=> x=1`

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

`<=> 4x^2-4x-3x^2+15-x^2=x-3-x-4`

`<=> -4x+15=-7`

`<=> -4x=-22`

`<=> x=11/2`

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

`<=>2(6x^2+15x-2x-5)-6(2x^2+4x-x-2)=-6`

`<=> 12x^2+26x-10-(12x^2+18x-12)=-6`

`<=> 12x^2+26x-10-12x^2-18x+12=-6`

`<=> 8x+2=-6`

`<=> 8x=-8`

`<=> x=-1`