Answer:
This is a quadratic function
write it in the form [tex]a(x-h)^2+k[/tex]
h and k is the vertex, meaning the coordinate that is lowest or highest point depending on where the function is...pointing. You can see that the function is point up, so h is the x coordinate is at the bottom. the vertex coordinate is (9, -4), im sure you know why. In the formula, h means the x and k is the y. So that means that the h is 9 and k is -4.
now the think will be [tex]a(x-9)^2-4\\[/tex]
now you find a by plugging one of the point, you can take the point (12, 4)
[tex]a(12-9)^2-4=4\\9a=8\\8/9=a\\[/tex]
so the equation
[tex]8/9 (x-9)^2 -4[/tex]
Step-by-step explanation: