Complex Arithmetic/Examples/Modulus of (z 1 conj z 2 + z 2 conj z 1)

Example of Complex Arithmetic
Let $z_1 = 1 - i$ and $z_2 = -2 + 4 i$.

Then:
 * $\cmod {z_1 \overline {z_2} + z_2 \overline {z_1} } = 12$