An evaluation morphism

Let zC be a complex number and let ϵz:R[x]C be the evaluation homomorphism given by ϵz(p)=p(z) for each pR[x].

  1. Show that ker(ϵz) is a prime ideal.
  2. Compute ker(ϵ1+i),im(ϵ1+i) and then state the conclusion of the First Isomorphism Theorem applied to the homomorphism ϵ1+i.