Show How:

http://latex.codecogs.com/png.latex?...2}{N})-\mu x^2

Becomes:

http://latex.codecogs.com/png.latex?...- \mu x)^2}{N}

I know how to do it the other way, but now it's asking me to do it this way and i'm confused.

Also, show how: http://latex.codecogs.com/png.latex?...sum x_i}{N})^2

Becomes: http://latex.codecogs.com/png.latex?...2}{N})-\mu x^2

Lastly, show how: http://latex.codecogs.com/png.latex?...2}{N})-\mu x^2

Becomes: http://latex.codecogs.com/png.latex?...sum x_i}{N})^2

I don't quite understand the expanding and/or simplifying i'm supposed to do. Any help is greatly appreciated.