How do you multiply $(8-7i)(6-4i)$ in trigonometric form?

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Answer 1 · 2018-01-27T01:53:06

$(8-7i)(6-4i) = 20-74i$

Whilst we could convert each complex number into trigonometric forms, it would be cumbersome to do so, instead we just expand the expression:

$(8-7i)(6-4i) = 8(6-4i) -7i(6-4i)$
$" " = 48-32i - 42i+28i^2$
$" " = 48-74i -28$
$" " = 20-74i$

How do you multiply (8-7i)(6-4i) (8-7i)(6-4i) in trigonometric form?