Tìm đa thức M biết rằng:
1)M+(5x^2-2xy)=6x^2+9xy-y^2
2)M+(2x^2y-2xy^3)=2x^2y-4xy^3
3)(2xy^2+x^2-x^2y)-M=-xy^2-x^2y+1
Tìm đa thức M biết rằng: 1)M+(5x^2-2xy)=6x^2+9xy-y^2 2)M+(2x^2y-2xy^3)=2x^2y-4xy^3 3)(2xy^2+x^2-x^2y)-M=-xy^2-x^2y+1
By Iris
By Iris
Tìm đa thức M biết rằng:
1)M+(5x^2-2xy)=6x^2+9xy-y^2
2)M+(2x^2y-2xy^3)=2x^2y-4xy^3
3)(2xy^2+x^2-x^2y)-M=-xy^2-x^2y+1
`1)M+(5x^2-2xy)=6x^2+9xy-y^2`
`=> M=(6x^2+9xy-y^2)-(5x^2-2xy)`
`=> M=6x^2+9xy-y^2-5x^2+2xy`
`=>M=(6x^2-5x^2)+(9xy+2xy)-y^2`
`=>M=x^2+11xy-y^2`
$2)M+(2x^2y-2xy^3)=2x^2y-4xy^3$
`=>M=(2x^2y-4xy^3)-(2x^2y-2xy^3)`
`⇒ M= 2x^2y-4xy^3-2x^2y+2xy^3`
`⇒ M=(2x^2y-2x^2y)+(-4xy^3+2xy^3)`
`⇒ M=-2xy^3`
`3)(2xy^2+x^2-x^2y)-M=-xy^2-x^2y+1`
`⇒ M=(2xy^2+x^2-x^2y)-(-xy^2-x^2y+1)`
`⇒ M= 2xy^2+x^2-x^2y+xy^2+x^2y-1`
`⇒ M= (2xy^2+xy^2)+(-x^2y+x^2y)+x^2-1`
`⇒ M= 3xy^2 + x^2 – 1`