`a)(5x^3-3x^2+2x+7):(x^2+1)`
`=(5x^3+5x-3x^2-3-3x+10):(x^2+1)`
`=[5x(x^2+1)-3(x^2+1)-3x+10]:(x^2+1)`
`=[(x^2+1)(5x-3)-3x+10]:(x^2+1)`
`=5x-3` và dư `10-3x`
`b)(6x^3-7x^2-x+2):(2x+1)`
`=(6x^3+3x^2-10x^2-5x+4x+2):(2x+1)`
`=[3x^2(2x+1)-5x(2x+1)+(2x+1)]:(2x+1)`
`=[(2x+1)(3x^2-5x+2)]:(2x+1)`
`=3x^2-5x+2`
`c(x^4-2x^3+2x-1):(x^2-1)`
`=(x^4-1-2x^3+2x):(x^2-1)`
`=[(x^2-1)(x^2+1)-2x(x^2-1)]:(x^2-1)`
`=[(x^2-1)(x^2-2x+1)]:(x^2-1)`
`=x^2-2x+1`
`d)(8x^3-6x^2-5x+3):(4x+3)`
`=(8x^3+6x^2-12x^2-9x+4x+3):(4x+3)`
`=[2x^2(4x+3)-3x(4x+3)+4x+3]:(4x+3)`
`=[(4x+3)(2x^2-3x+1)]:(4x+3)`
`=2x^2-3x+1`
