Answer:
-7
Step-by-step explanation:
If you look at the first number,count how many in between the next number and the one after that.
It is negative six because down three is -3 so 3+3 =6 but the numbers are negative so the answer is -6
1) (2i-4)-(6i+9) = 2i-4-6i-9 = -4i-13
2) (-3+8i)+(3-8i) = -3+8i+3-8i = 0+0i = 0
