~ Bạn tham khảo ~
`(5x-10)(x^2-1)-(3x-6)(x^2-2x+1)`
`= (5x-10)(x-1)(x+1)-(3x-6)(x-1)^2`
`= (x-1)[(5x-10)(x+1)-(3x-6)(x-1)]`
`= (x-1)[5(x-2)(x+1)-3(x-2)(x-1)]`
`= (x-1)(x-2)[5(x+1)-3(x-1)]`
`= (x-1)(x-2)(5x+5-3x+3)`
`= (x-1)(x-2)(2x+8)`
`= 2(x-1)(x-2)(x+4)`