Answer:
A c is subtraction AND f is adding
Step-by-step explanation:
Remove parentheses:
-4 - 6i + 3i - 8 + i
Combine common terms
-12 -2i
The pyhtagorean states that to find c, use the eqaution,

.
Substitute 1 for a and 20 for b;
c^2=1+400
c^2=401
c=
which is about 20.02
Hope this helps.