If a+ib is a root of the equation x2−ax+b, then (where i=√−1)
a+ιb is one root then a−ιb is another root
a=a+ιb+a−ιb
2a=a⇒a=0
(a+ιb)(a−ιb)=b
a2+b2=b
b=0,1