if |z-5i|/|z+5i| = 1, then show that z is a real number Share with your friends Share 18 Rishabh Mittal answered this Let z=a+ibz-5i=a+ib-5z+5i=a+ib+5z-5iz+5i=1a2+b-52a2+b+52=1a2+b-52=a2+b+52Squaring on both sides , we geta2+b-52=a2+b+52b2-10b+25=b2+10b+25-20b=0 b=0So, z=a , which is a real number. 73 View Full Answer