The equation $|z - 5i| / |z + 5i| = 12,$ where $z = x + iy,$ represents a/an

Given $z$ is a complex number such that $|z| < 2$,then the maximum value of $|iz + 6 - 8i|$ is equal to-

$z_1$ and $z_2$ are two fixed points on the Argand plane. If $z$ is a complex number such that $|z-z_1| + |z-z_2| = \lambda$,then the locus of $z$ is

If $z = x + iy$ is a complex number and $|1 + iz| = |1 - iz|$, then

If $z_1, z_2, z_3 \in \mathbb{C}$ such that $|z_1| = |z_2| = |z_3| = 2$,then the greatest value of the expression $|z_1 - z_2||z_2 - z_3| + |z_2 - z_3||z_3 - z_1| + |z_3 - z_1||z_1 - z_2|$ is

If the four points $A, B, C, D$ in the Argand plane represented respectively by the complex numbers $2+i, 4+3i, 2+5i, 3i$ lie on a circle,then the centre of the circle is