The vertex form of a quadratic function is in the form
- is a coefficient that needs to be found, and
- is the vertex of this function.
In this question, the vertex of this quadratic function is at the point . In other words, and . Substitute these value into the general equation:
Simplify to obtain:
The only missing piece here is the coefficient . That’s likely why the problem gave , yet another point on this quadratic function. If this function indeed contains the point , should be equal to when . That is:
Solve this equation for :
Hence the equation of the quadratic function in its vertex form: