[填空题]
The graph shows the curve of a quadf- 1hjz):8e5n+ s 6fw,igg c ubwphcu;ratic funcrossm +* i;2hlvxi9i38l bmx9tion of the form f(x)=$ax^2$+bx+90.
1.Write down the equation for the axis of symmetry of the curve. x =
2.Hence, or otherwise, find the value of a and the value of b. a = b =
3.Find the y-coordinate of the vertex of the curve. f(x) =