Help with x intercepts of a quadratic

how do you find the x intercept of a quadratic with only the vertex and x intercept or if you have a link to an online calculator for this that would be great

The x-intercepts are symmetric about the axis of symmetry which passes through the vertex.

If you are given the vertex, and one of the x-intercepts, it is easy to find the other x intercept.

The vertex gives you the qxis (line) of symmetry. The shape of the parabola is a reflection of the other side of the parabola.

Find the distance the given x-intercept is from the line of symmetry. The other x-intercept is the same distance away from the line of symmetry but is on the other side.