Answer:
For complex numbers,
a + bi and a - bi
they have the interesting property that if you add them you get the real number 2a
and if you multiply them , because of the difference of square pattern, you get a^2 - b^2 i^2
But since i^2 = -1, we end up with a real number as a product.
e.g. 6 - 5i and 6 + 5i are conjugates of each other
sum = 6-5i + 6+5i = 12
product = 36 - 25i^2
= 36 -(-25) = 61
Your question is even easier, since the denominator is a monomial instead of a binomial, so we just have to multiply by i/i
Also I believe, according to the answer, that you have a typo, and you meant
(-5+i)/(2i)
= (-5+i)/(2i) *i/i
= (-5i + i^2)/2i^2)
= (-5i +i^2)/-2
= (-5i - 1)/-2
= (1 + 5i)/2 or they way they have it: 1/2 + 5i/2
