The complex conjugate of 2-3i is also a root of z^3+pz^2+qz-13p=0. Find a quadratic factor of z^3+pz^2+qz-13p=0 with real coefficients and thus find the real root of the equation.
z-2+3i times z-2-3i = z2-4z+13. z3-2z2+5z+26 divided by z2-4z+13 = z+2. Therefore the real root is z=-2.
