<s>[INST] Let $a, b, c$ be real numbers such that $0<a \leq b \leq c$ and $f(x)=ax^2+bx+c$ is a quadratic function. Suppose that the graph of $y=f(x)$ has an axis of symmetry at $x=-\frac{b}{2a}$, and the point $(-2,0)$ lies on the graph of $y=f(x)$. Determine the values of $a, b, c$.[/INST]