Are these equivalent summations?

I just want to ask if
$$\sum_{i=1}^n \sum_{j=1}^i |a_i \bar b_j-a_j\bar b_i|^2 = \sum_{i=1}^n \sum_{j=1}^n (a_i \bar b_j-a_j\bar b_i)(\bar a_ib_j + \bar a_j b_i)$$

is true and possibly an explanation on why the summations change from $\sum^n$ to to $\sum^i$