(1) no question, no answer
(2) The expression as you show it, "8i/(3-i)(2-i)(4-i)", is ambiguous. Is it
8i
---------------
(3-i)(2-i)(4-i)
Or is it perhaps
8i
------ (2-i)(4-i)
(3-i)
Without any additional parentheses, the second interpretation is correct, according to standard rules for order of operations. If you want the first interpretation, you need to use parentheses to show that all three of the factors are in the denominator: 8i/((3-i)(2-i)(4-i))
Re-post your question, making it clear what the given expression is; then ask an actual question about it.