P(x)=(x−(1−i))(x−(1+i))(x−(2−2i))(x−(2+2i))(x2−cx+4) Since the first four roots are all distinct, the term (x2−cx+4) must be a product of any combination of two (not necessarily distinct) factors from the set (x−(1−i)),(x−(1+i)) (x−(2−2i))(x−(2+2i)). The only combinations are (x−(1−i))&(x−(2+2i)) or (x−(1+i))&(x−(2−2i)) ∴c=3±i |c|=√10