Đáp án:

 

Giải thích các bước giải:

`c)6x^2 -3x+(3x-2)(5-2x)=0`

`<=>6x^2 -3x +15x-6x^2-10+4x=0`

`<=>(6x^2-6x^2)+(-3x+15x+4x)=0+10`

`<=>16x=10`

`<=>x=(10)/(16)`

`<=>x=5/8`

Vậy `x=5/8`

`d)(-x+3)(3x+2)+x(3x+1)=0`

`<=>-3x^2 -2x+9x+6+3x^2+x=0`

`<=>(-3x^2+3x^2)+(-2x+9x+x)=0-6`

`<=>8x=-6`

`<=>x=-6/8`

`<=>x=-3/4`

Vậy `x=-3/4`

`e)(x-1)^2 -x(x+3)=0`

`<=>x^2 -2x+1 -x^2-3x=0`

`<=>(x^2-x^2)+(-2x-3x)=0-1`

`<=>-5x=-1`

`<=>x=1/5`

Vậy `x=1/5`

`f)(x-1)(x-3)-(x-2)(x-1)=9`

`<=>x^2-3x-x+3-(x^2-x-2x+2)=9`

`<=>x^2-3x-x+3-x^2+x+2x-2=9`

`<=>(x^2-x^2)+(-3x-x+x+2x)=9-3+2`

`<=>-x=8`

`<=>x=-8`

Vậy `x=-8`

`g)12x^2-4x(3x+5)=10x-17`

`<=>12x^2-12x^2-20x=10x-17`

`<=>(12x^2-12x^2)-20x-10x=-17`

`<=>(-20x-10x)=-17`

`<=>-30x=-17`

`<=>x=(17)/(30)`

Vậy `x=(17)/(30)`

`h)(x-5)(x-3)=(x-4)(x-1)`

`<=>x^2-3x-5x+15=x^2-x-4x+4`

`<=>x^2-8x+15-x^2+x+4x=4`

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

`<=>-3x=-11`

`<=>x=(11)/3`

Vậy `x=(11)/3`