[填空题]
The diagram below shows jf sq),9 7kpd65hhoo-0lkvd1atyo: f thc6w.aazfk7po b)/*fzz3xd2;*c u z6juk p jo*e graph of a quadratic function $f(x)=2 x^{2}+b x+c $.
1. Write down the value of c .
2. Find the value of b and write down f(x) .
3. Calculate the coordinates of the vertex of the graph of f .(a,b) a = b =