Question

How do you simplify `i^3 (5+i) + 7i`?

Answer 1

Answer is `1+2i`

Explanation:

To simplify `i^3(5+i)+7i`, remember `i^2=-1` and as `i^4=(i^2)^2`, `i^4=1`.

Hence `i^3(5+i)+7i`

= `5i^2*i+i^4+7i`

= `-5i+1+7i`

= `1+2i`