#1**+4 **

I am not the best at explaining, and I don't explain very much(new user and look at my username), so don't go attacking me. (I also skip like a lot of "simple" to me steps)

First, you can factor **z^4 - 4z^2 + 4 = 0** into **(z^2 -2)^2**

I am * assuming *that you already know this, but i will still "explain"

You can turn **z^4 - 4z^2 +4 = 0 **into **z^4 - 2z^2 - 2z^2 + 4**

Then, you notice that you can factor that into **z^2****(z^2 - 2) -2(z^2 - 2)**

Then, you can turn that into **(z^2 -2)(z^2-2). **Or, **(z^2 - 2)^2.**

You notice that \(\sqrt{2}\), will work, and **-\(\sqrt{2}\). **

Because, \((\sqrt{2})^2\)is equal to 0, **(2-2)^2 = 0**

And \((-\sqrt{2})^2\)is *also* equal to 2.

I hope this helped?

IAmBadAtSolving Apr 10, 2022