System of Equations

Let a be a real Number. Solve the system of equations:

http://www4b.wolframalpha.com/Calcul...s=21&w=85&h=18
http://www4b.wolframalpha.com/Calcul...s=61&w=85&h=18
http://www4b.wolframalpha.com/Calcul...s=14&w=85&h=18

What equations?

I guess the equations I used were deleted by the site. I am still trying to figure out LaTex. Solve the system for x,y,z,a

x+y+z=a
x^2+y^2+z^2=3a^2
(1/x)+(1/y)+(1/z)=(1/a)