Answer:
A=-3
Step-by-step explanation:
To begin, a parabola of form a(x-h)² +k opens upward when a is positive. Similarly, when a is negative, the parabola opens downward. Therefore, a must be negative here, as our expression for the parabola is a(x-0)²+0 = ax², with (0,0) being (h,k) and the vertex.
To determine whether a should be -3 or -0.6, we can think about the values on the graph that correspond to these values. A narrower graph would have a steeper slope. A narrower graph would have a large change in y with little change in x. Therefore, as ax² = y is our equation, and when a=-3, y changes more rapidly relative to when a = -0.6, A=-3 is our answer
