M=x^3+x^2y-2x^2-xy-y^2+3y+x-1 biết x+y-2=0 21/08/2021 Bởi Athena M=x^3+x^2y-2x^2-xy-y^2+3y+x-1 biết x+y-2=0
`x+y-2=0` `⇔x+y=2` `M=x^3+x^2y-2x^2-xy-y^2+3y+x-1` `⇔M=x^2(x+y-2)-y(x+y-2)+y+x-1` `⇔M=0-0+2-1` `⇔M=1` Bình luận
`x+y-2=0`
`⇔x+y=2`
`M=x^3+x^2y-2x^2-xy-y^2+3y+x-1`
`⇔M=x^2(x+y-2)-y(x+y-2)+y+x-1`
`⇔M=0-0+2-1`
`⇔M=1`