Analyze the key characteristics of the following quadratic function. f(x)=x2‒9 Based on the graph, which statement is not true? A. The y-intercept is the same point as the vertex. B. The graph increases in the interval 0 to ∞. C. The graph is always positive. D. The zeros of this function are at 3 and ‒3.

C. The graph is always positive.

Explanation:

To solve this, it is basically a process of elimination. A is true since the -9 indicates the function was translated down 9 units, making the vertex lie on the y-axis. B is also true because if you look at the equation from 0 to infinity, the y-values increase. D is also correct because when you solve for the zeros, they do end up being 3 and -3, making the only claim that is not true C, the graph is always positive.