Question

Find the modulus of the following numbers:

z=(1+3i)(2-i)​

Answer 1

$z = (1 + 3i)(2 - i)$

$= 5 + 5i$

$|z| = \sqrt{ {(5)}^{2} + {(5i)}^{2} }$

$= \sqrt{20}$

$|z| = 2 \sqrt{5}$