z1=x1+iy1 and z2=x2+iy2 and z1−z2=(x1−x2)+2(y1−y2)
arg(z1−z2)=π4⇒tan−1(y1−y2x1−x2)=π4
⇒y1−y2=x1−x2⋯(i)
⇒|z−3|=Re(z)⇒|(x−3)+2y|=x
⇒(x−3)2+(y)2=x2
⇒y2=6(x−32)
Let the point on this parabola
(32+at21,2at1) and (32+at22,2at2), where a=64
∵y1−y2=x1−x2
⇒2a(t1−t2)=a(t21−t22)
⇒t1+t2=2
Now, Im(z1+z2)=y1+y2
=2a(t1+t2)
=2×64(2)=6