4/-3i

why is the answer a positive number
4/-3i *3i/3i = 12i/9 = 4i/3 or 4/3i

why isn't it 12/-9i?

thank you

it is 12/-9i

But if you want your answer to be a complex number a+bi then you realize that since
i^2 = -1
-i^2 = 1
1/i = -i
4/-3i = 4/-3 * 1/i = 4/-3 * -i = 4/3 i