I have the function $f:\Bbb R^3 \to \Bbb R$, $f:(x,y,z)\mapsto x^2+y^2+z^2+2x+5$
What does some $A\in\Bbb R$ look like in the preimage of this function? How do I work that out?
It's strange, apparently this is bijective, but then what about $(x,a,b)$ and $(x,b,a)$ these should map to the same place, so not injective? If it's not bijective, that doesn't matter I guess for finding the preimage, but I can't work it out.