Question

Find the product of (3 + 7i)(1 − i), and write the answer in standard form.

Answer 1

(3 + 7i)(1 − i)

==> 3*1 - 3*i + 7i*1 - 7i*i

==> 3 - 3i + 7i - 7i^2

===> -7i^2+4i+3

==> -7i^2+7i - 3i + 3

==> -7i(i-1) - 3(i-1)

==> (i-1) (-7i-3)