Đáp án+Giải thích các bước giải:
`4)`
`a)x^4+2x^3+3x^2+2x+2 `
`=x^4+2x^3+2x^2+x^2+2x+2 `
`=(x^4+2x^3+2x^2)+(x^2+2x+2) `
`=x^2(x^2+2x+2)+(x^2+2x+2) `
`=(x^2+1)(x^2+2x+2) `
`b) x^4+3x^3+10x^2+12x+24`
`=x^4+3x^3+6x^2+4x^2+12x+24`
`=(x^4+3x^3+6x^2)+(4x^2+12x+24)`
`=x^2(x^2+3x+6)+4(x^2+3x+6)`
`=(x^2+4)(x^2+3x+6)`
`c) x^4-2x^2+12x-8`
`=x^4+2x^3-2x^3-2x^2-4x^2+4x^2+4x+8x-8`
`=(x^4+2x^3-2x^2)-(2x^3+4x^2-4x)+(4x^2+8x-8)`
`=x^2(x^2+2x-2)-2x(x^2+2x-2)+4(x^2+2x-2)`
`=(x^2-2x+4)(x^2+2x-2)`