Giúp mình với cám ơn mn

`a.`

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

`<=>2x^2 +3x^2 -3-5x^2 -5x=0`

`<=>-5x-3=0`

`<=>-5x=3`

`<=>x=-3/5`

Vậy `x=-3/5`.

`b.`

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

`<=>3x^2 +3x-3x^2 -6x+x=-1`

`<=>-2x=-1`

`<=>x=1/2`

Vậy `x=1/2`.

`c.`

`(3x-5)(7-5x)-(5x+2)(2-3x)=4`

`<=>-15x^2 +46x-35+15x^2 -4x-4=4`

`<=>42x-39=4`

`<=>42x-43=0`

`<=>42x=43`

`<=>x=43/42`

Vậy `x=43/42`.

`d.`

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

`<=>4(x^2 +4x-5)-(x^2 +7x+10)=3(x^2 +x-2)`

`<=>4x^2 +16x-20-x^2 -7x-10=3x^2 +3x-6`

`<=>3x^2 +9x-30=3x^2 +3x-6`

`<=>3x^2 -3x^2 + 9x-3x=-6+30`

`<=>6x=24`

`<=>x=4`

Vậy `x=4`.