（-x^2y^m）^2*(kx^n+1y)
=x^4y^2m*(kx^n+1y)
=kx^(n+5)*y^(2m+1)
=-2x^6y^3,
k=-2,n+5=6,2m+1=3
m=n=1
(k^m)^n=k=-2