Đáp án + Giải thích các bước giải:
a)
Sắp xếp:
+ `A(x)=2x^3-3x^2+2x+1`
+ `B(x)=3x^3+2x^2-x-5`
b)
`A(x)+B(x)=2x^3-3x^2+2x+1+3x^3+2x^2-x-5`
`=>A(x)+B(x)=(2x^3+3x^3)-(3x^2-2x^2)+(2x-x)+(1-5)`
`=>A(x)+B(x)=5x^3-x^2+x-4`
c)
`A(x)-B(x)=(2x^3-3x^2+2x+1)-(3x^3+2x^2-x-5)`
`=>A(x)-B(x)=2x^3-3x^2+2x+1-3x^3-2x^2+x+5`
`=>A(x)-B(x)=(2x^3-3x^3)-(3x^2+2x^2)+(2x+x)+(1+5)`
`=>A(x)-B(x)=-x^3-5x^2+3x+6`