Answer
$z\cdot\overline{z}=25$
Work Step by Step
$z=3-4i$ $;$ $w=5+2i$
$z\cdot\overline{z}$
Multiply the complex number $z$ by its conjugate. To obtain the conjugate, change the sign of its imaginary part:
$z\cdot\overline{z}=(3-4i)(3+4i)=3^{2}-(4i)^{2}=9-16i^{2}=...$
Substitute $i^{2}$ by $-1$ and simplify:
$...=9-16(-1)=9+16=25$
