[填空题]
The graph shows the c(8 lk7kvx9 0 b*ya4ebelg9bg ayja(tet1ox 3+wos i5iag n35zkw)v /( urve of a quadratic function of the form $ f(x)=a x^{2}+b x+90 $.
1. Write down the equation for the axis of symmetry of the curve.
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.
