a^2+b^2+c^2=25,(1)
x^2+y^2+z^2=25,(2)
ax+by+cz=25,(3)
(1)+(2)-2*(3)
a^2+b^2+c^2+x^2+y^2+z^2-2ax-2by-2cz=0,
(a-x)²+(b-y)²+(c-z)²=0
a=x,b=y,c=z
(2007a+5b+8c)/(2007x+5y+8z)=1
a^2+b^2+c^2=25,(1)
x^2+y^2+z^2=25,(2)
ax+by+cz=25,(3)
(1)+(2)-2*(3)
a^2+b^2+c^2+x^2+y^2+z^2-2ax-2by-2cz=0,
(a-x)²+(b-y)²+(c-z)²=0
a=x,b=y,c=z
(2007a+5b+8c)/(2007x+5y+8z)=1