Question

关于xy的多项式6*m*x的2次方+4*n*x*y+2*x+2*x*y-x的2次方+y+4不含二次项,求6*m-2*

Answer 1

=(6mx)^2+4nxy+2x+2xy-x^2+y+4

=36m^2x^2+4nxy+2x+2xy-x^2+y+4

=(36m^2-1)x^2+(4n+2)xy+(2x+y)+4

由题意所知得 36m^2-1=0

即 m=±1/6

当m=1/6 时 6m-2=6*1/6-2=-1

当m=-1/6 时 6m-2=6*(-1/6)-2=-3