# Proof of equation

1. Apr 25, 2014

### trenekas

Hi there. I need some help to prove one equation.

There is my solution but something is wrong i think.

Any help would be appreciated :)

2. Apr 25, 2014

### LCKurtz

You should be able to simplify each side to$$\sum_{i=1}^n (X_iY_i) - n\bar X \bar Y$$