Answer
$6$
Work Step by Step
$\bf{\text{Solution Outline:}}$
To simplify the given expression, $
(3-4i)-(-3-4i)
,$ remove the grouping symbols. Then combine the real parts and the imaginary parts.
$\bf{\text{Solution Details:}}$
Removing the grouping symbols, the given expression is equivalent to
\begin{array}{l}\require{cancel}
3-4i+3+4i
.\end{array}
Combining the real parts and the imaginary parts results to
\begin{array}{l}\require{cancel}
(3+3)+(-4i+4i)
\\\\=
6+0
\\\\=
6
.\end{array}