Question 534174
I'm confused. Maybe something got mixed up in the text of the problem or the previous answer.
Were you supposed to add the two complex numbers or multiply them?
If adding
{{{(7-6i)+(9+11i)=(7+9)+i(-6+11)=16+5i}}}
When working with complex numbers, you work as if the i was a variable x.
You cannot mix the real part of the number, with the imaginary part that has the i, just like you cannot add 16+5x.
The only difference is that the even powers of i are real numbers, so multiplications of complex numbers can always simplify to something as short as {{{16+5i}}}
{{{i^2=-1}}}, {{{i^4=1}}} and all {{{i^evennumber}}} powers simplify to {{{1}}} (if the exponent is a multiple of 4) or to {{{-1}}} (if not a multiple of 4).