关于x,y的多项式6mx2+4nxy+2x+2xy-x2+y+4不含二次项,求6m-2n+2的值.

问题描述:

关于x,y的多项式6mx2+4nxy+2x+2xy-x2+y+4不含二次项,求6m-2n+2的值.

∵多项式6mx2+4nxy+2x+2xy-x2+y+4=(6m-1)x2+(4n+2)xy+2x+y+4不含二次项,
即二次项系数为0,
即6m-1=0,
∴m=

1
6

∴4n+2=0,
∴n=-
1
2
,把m、n的值代入6m-2n+2中,
∴原式=6×
1
6
-2×(-
1
2
)+2=4.