Try this beautiful problem from AIME, 2009 based on complex numbers.

## Complex Numbers – AIME, 2009

There is a complex number z with imaginary part 164 and a positive integer n such that $\frac{z}{z+n}=4i$, Find n.

- 101
- 201
- 301
- 697

**Key Concepts**

Complex Numbers

Theory of equations

Polynomials

## Check the Answer

Answer: 697.

AIME, 2009, Problem 2

Complex Numbers from A to Z by Titu Andreescue .

## Try with Hints

Taking z=a+bi

then a+bi=(z+n)4i=-4b+4i(a+n),gives a=-4b b=4(a+n)=4(n-4b)

then n=$\frac{b}{4}+4b=\frac{164}{4}+4.164=697$

## Other useful links

- https://www.cheenta.com/geometry-of-plane-figures-pre-rmo-2019/
- https://www.youtube.com/watch?v=65RRPvbATsk