`A(x)=2x^4+5x^3-x^2+2x+2`
`B(x)=-x^4-5x^3+3x^2-2x+1`
`\to A(x)-B(x)`
`=(2x^4+5x^3-x^2+2x+2)-(-x^4-5x^3+3x^2-2x+1)`
`=2x^4+5x^3-x^2+2x+2+x^4+5x^3-3x^2+2x-1`
`=(2x^4+x^4)+(5x^3+5x^3)+(-x^2-3x^2)+(2x+2x)+(2-1)`
`=3x^4+10x^3-4x^2+4x+1`
Vậy `A(x)-B(x)=3x^4+10x^3-4x^2+4x+1`