To simplify (6 - 4i) - (і +5), you have to apply associative property.
First step is to remove the parenthesis, then you have:
[tex]6\text{ - 4i - i + 5}[/tex]Now collect like terms:
[tex]\begin{gathered} 6\text{ + 5 - 4i - i} \\ =\text{ 11 - 5i} \end{gathered}[/tex]ANSWER:
[tex]11\text{ - 5i}[/tex]