Question

Perform the indicated operation and express the result as a simplified complex number. (5−6i)(4+8i)

Answer 1

we have the expression

`(5-6i)(4+8i)`

Apply distributive property

`\begin{gathered} (5)(4)+(5)(8i)-(6i)(4)-(6i)(8i) \\ 20+40i-24i-48i^2 \\ Reemmber\text{ that }i^2=-1 \\ 20+40i-24i-48(-1) \\ 20+40i-24i+48 \\ combine\text{ like terms} \\ (68+16i) \end{gathered}`