Question

How do you simplify `(5 - 7i) (2 - 5i)`?

Answer 1

`-25-39i`

Explanation:

We need to multiply each term in the first set of parentheses by each term in the second set of parentheses. We can write this as follows:

`5(2-5i)-7i(2-5i)`

Now we distribute the `5` and `-7i`. This will give us:

`10 - 25i-14i+35i^2`

Combine like terms and remember that `i^2=-1` This will give us:

`10-39i+35(-1)`
`10-39i-35`
`-25-39i`