Multiply and show all steps please!!

the answer is 80 take the positive and negative and use the sign change rule
Answer:
50
Step-by-step explanation:
First, find the square roots.
[tex]\sqrt{-16} =4i[/tex]
[tex]\sqrt{-64} =8i[/tex]
Remember: i stands for [tex]\sqrt{-1}[/tex]
Then use the FOIL method to multiply.
(3+4i)(6-8i)
18-24i+24i-32i²
i²= -1, so :
18+32
50
I have no idea what the other person did, but its wrong.