Answer
$=-7-24i$.
Work Step by Step
The given expression is
$=(3-4i)^2$
Use the special formula $(A-B)^2=A^2-2AB+B^2$.
We have $A=3$ and $B=4i$.
$=(3)^2-2(3)(4i)+(4i)^2$
Simplify.
$=9-24i+16i^2$
Use $i^2=-1$.
$=9-24i+16(-1)$
Simplify.
$=9-24i-16$
$=-7-24i$.
