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.
答
∵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=-
,把m、n的值代入6m-2n+2中,1 2
∴原式=6×
-2×(-1 6
)+2=4.1 2