Question

How do you do this one?

Answer 1

Your answer is correct...
`i^2=-1`, so

`(3+i)(i^2+8i-2)=(3+i)(-3+8i)`

Then distributing
`3+i` to both terms on the right gives

`(3+i)(-3)+(3+i)(8i)=(-9-3i)+(24i+8i^2)=-9-3i+24i-8=-17+21i`