What does the a stand for in y equals ax2 plus bx plus c?

y = ax2 + bx + c

The graph is always a parabola.

'a', 'b', and 'c' are numbers. Different values for 'a', 'b', and 'c' produce parabolas with different widths,

noses at different heights and different left-right locations. They determine whether the parabola

opens up or opens down, and whether it crosses the 'x' and 'y' axes, and if so, where it crosses.