Question 169994
Well equations of the form of {{{y=ax^2+bx+c}}} where "a" is positive model parabolas that open upward. 



For instance, a parabola opening upward would look like this:



{{{ drawing(500, 500, -10, 10, -10, 10,
 graph( 500, 500, -10, 10, -10, 10,(x-2)^2)

)}}}



Since the left side of the graph starts high, decreases, and then eventually increases, this means that a parabola would fit the data. So an equation of the form {{{y=ax^2+bx+c}}} should model the data.