How do i know if a parabola is wide or narrow?

Depends on the intervals that make it wide or narrow. But from the looks of the vertex and knowing the properties of a parabola, I would say this neither wide or narrow. The parabola will open up wider each time the leading coefficient becomes smaller, but has to be 0 < a < 1. It will become more compressed each time the leading coefficient gets larger. 1 < a < inf