Which coordinates do a, B and C of y = ax ^ 2 + BX + C in quadratic function image represent?

Which coordinates do a, B and C of y = ax ^ 2 + BX + C in quadratic function image represent?

Quadratic function y = ax ^ 2 + BX + C
1. Maximum (minimum) value: a > 0, when x = - B / (2a), y has the minimum value, which is y = a * (B / (2a)) ^ 2-B ^ 2 / (2a) + C
When x = - B / (2a), y increases with the increase of X
a