Quadratic Integer Rings

Quadratic Integer Rings

Let d>2 be a square free integer. 1.Prove that Z[d^1/2] is not a UFD.
2.For d=7 prove that for any posiotive integer n,the elemant 8^n in
Z[(-7)^1/2] is simultaneously a product of N irreducibles,for each
N=2n,2n+1 ,.....3n.