# why the sum of residuals must always equal zero?

#### MarginOfBuffett

##### New Member
Hello,

I was wondering why the sum of the residuals of a simple regression line must always equal zero. It simply blows my mind that it could always be true. Please help me wrap my mind around this concept.

Thanks,
MofB

#### Dason

Uh... That's pretty much one of the only terms that doesn't evaluate to 0. $$\sum(x_i - \bar{x})$$ is 0 though so when you multiply r(sy/sx) by 0 you get 0.