Pick a letter and an equation to solve for it in.
I will pick z and the second equation to solve for z in:
Substitute 
for z in the other two
equations, (but not the same one you just used)
Substituting it in
Substituting it in
Now you just have this simple system:
and I'll bet you can finish that by yourself, just by
substituting back
Answer x=2, y=1, z=-1
Edwin
