Question

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

Answer 1

`(5+3i)(3-i)=18+4i`

Explanation:

When we exercise arithmetic operations using complex numbers, particularly multiplication and / or division, one thing which needs to be remembered is that `i^2=-1`

Hence `(5+3i)(3-i)`

= `5xx3-5xxi+3ixx3+3ixx(-i)`

= `15-5i+9i-3i^2`

= `15-5i+9i-3(-1)`

= `15-5i+9i+3`

= `18+4i`