Question

How do you simplify `(2+6i)(2-9i)`?

Answer 1

`58-6i`

Explanation:

You can expand the expression by multiply it or (FOIL).

Given : `" "(2+6i)*(2-9i)`

`=>4- 18 i +12 i -54i^2`

`=>4- 6i -54i^2" "` Combined like terms

Remember `" "color(red)(i^2 = -1)`

Replace `-1` for `i^2`

`=> 4-6i -54(color(red)(-1))`
`=>4-6i + 54`

`=>58-6i`