[填空题]
Let $f(x)=3 x^{2}+12 x+9$ , for $x \in \mathbb{R}$ .
1. For the graph of f , find:
1. the y -intercept; (a,b) a = b =
2. the x -intercepts.
The function f can be written in the form $f(x)=a(x-h)^{2}+k$ . B (a,b) a = b = C(c,d) c = d =
2. Find the values of a, h and k .a = h = k =
3. For the graph of f , write down:
1. the coordinates of the vertex; (a,b) a = b =
2. the equation of the axis of symmetry.x =
The graph of a function g is obtained from the graph of f by a reflection in the x -axis, followed by a translation by the vector $ \binom{0}{4}$ .
4. Find g(x) , giving your answer in the form $g(x)=p x^{2}+q x+r$ .
