[填空题]
Let $f(x)=-6 x^{2}+b x+c$ , for x $\in \mathbb{R}$ , where b, c $\in \mathbb{Z}$ .
1. A horizontal line, L , intersects the graph of y=f(x) at (-1, h) and (5, h) , where $h \in \mathbb{R}$ .
1. Find the equation of the axis of symmetry of the graph of y=f(x) .
2. Hence show that b=24 .
2. Given h=-8 , find the value of c .
