What is the equation of the following graph in vertex form (0,12) (2,0) (4,-4) (6,0)

X value is going up and y value is moving up and down. So, it's look like a quadratic function. y intercept is 12 and x intercept is 2 and 6. and vertex is (4,-4). than f (x) = a (x-4) ^2+4. and put (0,12). and 16a+4=12. a=1/2. f (x) = 1/2x^2-4x+12 or 1/2 (x-4) ^2+12