(4 + i)(1 - 5i)
First, expand to get rid of parentheses.
\(4 - 20i + i + 5\)
Second, gather the like terms which contain the same variables.
\((4+5) + (-20i + i)\)
Third, add 4 + 5.
\(9 + (-20i + i)\)
Fourth, subtract -20i + i.
\(9 - 19i\)
Answer: 9 - 19i
