Question

How do you simplify `(-3 + i)(2 + 7i)`?

Answer 1

`(-3+i)(2+7i)=-13-19i=-(13+19i)`

Explanation:

Remembering that `i^2=-1`

You can think that `(a+ib)` is like a binomial, thus:

`(-3+i)(2+7i)=(-3times2-3times7i+2timesi+7i^2)=`

`=-6-21i+2i+7times(-1)=(-6-7)+(-21+2)i=-13-19i=-(13+19i)`