Question

Express (15 - 20i)/(1-2i) in a+bi form.

Thank you for all of the help!

Answer 1

since (a-bi)(a+bi) = a^2+b^2, we have

(15-20i)(1+2i)
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(1-2i)(1+2i)

= (15-20i+30i-40i^2)/(1^2+2^2)
= (55+10i)/5
= 11+2i

Answer 2

Thank you so much for your help Steve!