m²+2n²+2p²-2mn-2np-6p+9=0
m²-2mn+n²+p²-6p+9+n²-2np+p²=0
(m-n)^2+(p-3)^2+(n-p)^2=0
(m-n)^2=0,m=n
(p-3)^2=0,p=3
(n-p)^2=0,n=p
所以
m=n=p=3
m分之n²p
=27除以3
=9