Instead of doing your problem for you, I'll do one exactly like it that uses
exactly the same steps.  I'll do this one instead and you can use it as a
model to go by:

x = -5i; x = 5i; x = 3;

x + 5i = 0; x - 5i = 0; x - 3 = 0

Multiply left and right sides together

(x + 5i)(x - 5i)(x - 3) = 0

Multiply the first two parentheses using FOIL:



Since i2 = -1 substitute that:





Use FOIL again:



So f(x) is a constant k times the left side of that:



Since f(2) = 116, we substitute x=2

















 


Now do yours exactly the same way.

Edwin