A(x) = 2x^4 + 5x^3 -x^2 + 2x+2 B(x) = -x^4 – 5x^3 + 3x^2 – 2x + 1 Tính A(x) – B(x) 11/07/2021 Bởi Gabriella A(x) = 2x^4 + 5x^3 -x^2 + 2x+2 B(x) = -x^4 – 5x^3 + 3x^2 – 2x + 1 Tính A(x) – B(x)
`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` Bình luận
`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` Bình luận
`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`
`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`