1楼错了. 1. (m^2-6m+9)+(n^2+10n+25)=0 (m-3)^2+(n+5)^2=0 m-3=0 n+5=0 m=3 n=-5 m+n=3-5=-2 2. (10n+5)^2=n*(n+1)*100+5^2 2005^2=200*(200+1)*100+5^2=4020025