Question

The expression 10/(3 + i) is equivalent to:

1) 3 - i
2) (15 + 5i)/4
3) 3 + i
4) 5/4

Answer 1

the answer is 2) (15 + 5i)/4

proof
10/(3 + i)=10 (3 - i)/(3 + i) (3 - i)= 5(3 - i) /4