You can put this solution on YOUR website! The extreme point is right between the zeros. the leading term when you multiply to put into general form ( although you don't really need this in general form) is 2x^2, so the parabola will have a minimum.
The zeros will be when 2x-6=0 and when x-7=0. Find that middle value, plug it into the function, and that's you minimum y value.