B |a, b, c, d ez under addition. let h = 67. let g = [a b egia+ b+c+d = 0. prove that h is a subgroup of g. d what if o is replaced by 1? of ol show tha

b |a, b, c, d EZ under addition. Let H = 67. Let G = [a b EGIa+ b+c+d = 0. Prove that H is a subgroup of G. d What if O is replaced by 1? of oL Show tha