Correct. Rearrange the sum to put like terms together, then combine those like terms:

$\displaystyle{\left(-{9}+{4}{i}\right)}+{\left({4}-{2}{i}\right)}={\left(-{9}\right)}+{4}+{4}{i}-{2}{i}=-{5}+{2}{i}\usepackage{cmbright}\Huge\$