Which must be true of a quadratic function whose vertex is the same as its y-intercept? the axis of symmetry for the function is x = 0. the axis of symmetry for the function is y = 0. the function has no x-intercepts. the function has 1 x-intercept.

The axis of symmetry is x = 0
This is basically saying that the axis of symmetry is the vertical y axis

The vertex is either the highest point or the lowest point on the parabola, depending on what the value of 'a' is. If the vertex is the y intercept, then the vertex is on the y axis. The axis of symmetry goes through the vertex.