Bài 2 :Cho P(x) = 3x - 2x² - 2 + 6x³ Q(x) = 3x² - x -2x³ +4 R(x) = 1 + 4x³ - 2x b, P(x) - Q(x) Q(x) - P(x) P(x) - R (x) R(x) - P(x) Q(x) - R(x) R(x) - Q(x)

`P(x)- Q(x)`
`= (3x - 2x^2 - 2 + 6x^3)-(3x^2 - x -2x^3 +4)`
`= 3x-2x^2-2+6x^3-3x^2+x+2x^3-4`
`= (6x^3 +2x^3)-(2x^2+3x^2)+(3x+x)-(2+4)`
`= ( 6 + 2 ) . x^3 - ( 2 + 3 ) . x^2 + ( 3 + 1 ) . x - ( 2 + 4 ) `

`= 8x^3-5x^2+4x-6`
`Q(x)-P(x)`
`= (3x^2 - x -2x^3 +4)- (3x - 2x^2 - 2 + 6x^3)`
`= 3x^2-x-2x^3+4-3x+2x^2+2-6x^3`
`= -(2x^3+6x^3)+(3x^2+2x^2)-(x+3x)+(4+2)`
`= - ( 2 + 6 ) . x^3 + ( 3 + 2 ) . x^2 - ( 1 + 3 ) . x + ( 4 + 2 ) `
`= -8x^3+5x^2-4x+6`
`P(x)-R(x)`
`= (3x - 2x^2 - 2 + 6x^3)-(1+4x^3-2x)`
`= 3x-2x^2-2+6x^3-1-4x^3+2x`
`= (6x^3-4x^3)-2x^2+(3x+2x)-(2+1)`
`= ( 6 - 3 ) . x^3 - 2x^2 + ( 3 + 2 ) . x - ( 2 + 1 ) `
`= 2x^3-2x^2+5x-3`
`R(x) - P(x)`
`= (1+4x^3-2x)-(3x - 2x^2 - 2 + 6x^3)`
`= 1+4x^3-2x-3x+2x^2+2-6x^3`
`= (4x^3-6x^3)+2x^2-(2x+3x)+(1+2)`
`= ( 4 - 6 ) . x^3 + 2x^2 - ( 2 + 3 ) . x + ( 1 + 2 ) `
`= -2x^3+2x^2-5x+3`
`Q(x) - R(x)`
`= (3x^2 - x -2x^3 +4)-(1+4x^3-2x)`
`= 3x^2-x-2x^3+4-1-4x^3+2x`
`= -(2x^3+4x^3)+3x^2-(x-2x)+(4-1)`
`= - ( 2 + 4 ) . x^3 + 3x^2 - ( 1 - 2 ) . x + ( 4 - 1 ) `
`= -6x^3+3x^2+x+3`
`R(x)-Q(x)`
`= (1+4x^3-2x)-(3x^2 - x -2x^3 +4)`
`= 1+4x^3-2x-3x^2+x+2x^3-4`
`= (4x^3+2x^3)-3x^2-(2x-x)+(1-4)`
`= ( 4 + 2 ) . x^3 - 3x^2 - ( 2 - 1 ) . x + ( 1 - 4 ) `
`= 6x^3-3x^2-x-3`