要使多项式mX3+3nxY2+2X3-xY2+y不含3次项,则2m+3n=?

问题描述:

要使多项式mX3+3nxY2+2X3-xY2+y不含3次项,则2m+3n=?

mX3+3nxY2+2X3-xY2+y
=(m+2)x^3+(3n-1)xy^2+y不含3次项,则:
m+2=0
3n-1=0
m=-2
n=1/3
2m+3n=-4+1=-3