The answer is x=2+5i or 2-5i
If

denotes the sum of the first

terms of a geometric series with first term

and common ratio

, then





Using summation notation, you have

In this case, you have

,

, and

. So the value of the sum is

Rounded to the nearest whole number, the answer would be 3.
6 penalties/8 penalties
16 min/21.3
Y=8,4,2,-2 linear and in that order