解：[3x^(n-6)y^(-3-m)]*[-4x^(3m+1)y^(2n)=-12x^(n-6+3m+1)y^(-3-m+2n)=-12x^(3m+n-5)y^(2n-m-3)∵其与-x^4y是同类项∴3m+n-5=42n-m-3=1解得：m=2 n=3∴m^n+n^m=2³+3²=17
