[填空题]
The diagram below shows the graph of a quadr yu;u-k7m68dlv :mfi4 a3l+oyj oe ifp:1jnu9atq 4/i ./ltz3j/toih m8uyclk,l / mt(aic 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 =