Engineering Board Exam Reviewer · Complex Numbers: Operations · medium

Divide: 3+4i/1-2i

1. -1+2i
2. 1+2i
3. -1-2i
4. 5+2i

Answer

A. -1+2i

Solution

Multiplying by the conjugate: (3+4i)(1+2i)/12+22=3+6i+4i-8/5=-5+10i/5=-1+2i.

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