Which expression is equivalent to (9 + 3i) - (-4 + i)?
A. 5 + 2i
B. 5 + 4i
C. 13 + 2i
D. 13 + 4i

Answer:
c.
Step-by-step explanation:
from the expression (9 + 3i) - (-4 + i);
STEP 1: multiply (-4 + i) by the minus sign before it.
we have +4 - i as the result.
we are left now with:
9+3i+4-i.
STEP 2: grouping those with same values,
9+4+3i-i= 13+2i