If the eight vertices of a regular octagon in the complex plane are given by the complex numbers zj = 1xj - 2i (where j = 1, 2, ..., 8 and xj are real numbers), then the radius of the circumcircle of this octagon is:

If z is a complex number satisfying the relation |z + 1| = z + 2(1 + i), then z is:

z1, z2 and z3 are the vertices of an equilateral triangle inscribed in the circle |z| = 2. If z1 = 1 + i√3, then the values of z2 and z3 are:

The value of the expression x3 - 5x2 + 33x - 19, where x - 2 = 5i, is equal to: