Solve and simplify

Question

(3+9i)-(12-5i)

8+6i/7-5i

Answer 1

Rewrite as:

3+9i-12+5i

Add like terms:

-9+14i is your answer.

Answer 2

for the 2nd, multiply top and bottom by 7+5i

(8+6i)/(7-5i) * (7+5i)/(7+5i)
=(56 + 40i + 42i + 30i^2)/(48 - 25i^2)
= (26 + 82i)/73 . remember i^2 = -1