1, where a is greater than zero, the opening is upward, less than zero, and the opening is downward, which equals zero, that is, the straight Y axis.

2. The axis of symmetry is the Y axis (this function is the abscissa of the coordinates of the vertex of the axis of symmetry, that is, the straight line parallel to the Y axis, and the function is expressed as x=0).

Supplement: the constant k has no effect on this problem, but only on the y value of vertex coordinates.