Question

多项式6mx^2+4nxy+2x+2xy-x^2+y+4不含二次项,则6m-2n+2=?

Answer 1

∵6mx^2+4nxy+2x+2xy-x^2+y+4

=(6m-1)x^2+(4n+2)xy+2x+y+4

其中不含二次项,

∴二次项系数6m-1=0,4n+2=0,

解得:m=1/6,n=-1/2

∴6m-2n+2

=6×1/6-2×(-1/2)+2

=1+1+2

=4