Assume that no denominator equals 0.
2+i/1-3i
= 2+i/1-3i
= (2+i/1-3i) * (1+3i/1+3i)
= (2+3i^2)/(1-9i^2)
= (2/1) - (1/3i)
= 2-1/3i(answer)
no.... from your
(2+i/1-3i) * (1+3i/1+3i)
= (2+i)/(1-3i) * (1+3i)/(1+3i)
= (2 + 6i + i - 3i^2)/(1 - 9i^2) remember i^2 = -1
= (5+7i)/10