Question

已知多项式3x+my-8与多项式-nx+2y+7的差中,不含x、y项,求n的m次方+mn的值

Answer 1

(3x+my-8)-(-nx+2y+7)=(3x+nx)+(my-2y)+(-8-7),

不含x、y项,说明：(3x+nx)=0,(my-2y)=0,解得：n=-3; m=2.

n的m次方+mn

=(-3)²+2*(-3)

=9-6

=3