So here's the question:
Given a collection of points $(x_1,y_1), (x_2,y_2),\ldots,(x_n,y_n)$, let $x=(x_1,x_2,\ldots,x_n)^T$, $y=(y_1,y_2,\ldots,y_n)^T$, $\bar{x}=\frac{1}{n} \sum\limits_{i=1}^n x_i$, $\bar{y}=\frac{1}{n} \sum\limits_{i=1}^n y_i$.
Let $y=c_0+c_1x$ be the linear function that gives the best least squares fit to the points. Show that if $\bar{x}=0$, then $c_0=\bar{y}$ and $c_1=\frac{x^Ty}{x^Tx}$.
I've managed to do all the problems in this least squares chapter but this one has me completely and utterly stumped. I'm not entirely sure what the question is even telling me in terms of information nor do I get what it's asking. Any ideas on where to start?