So, the x value in vertex form has to be set equal to 0, as you’re solving for x. In this case, you’re given x=3, so do the opposite, make the x=3 equal to o.
x=3
x-3=0
Then the 4 is represented with the same value on the function as it is on the graph. If the y value of the vertex is negative on the grapgh, then it’s also negative in the function. If its positive on the graph its positive on the function. With x, if the x value of the vertex is negative on the graph, its positive in the equation. And if it’s positive on the graph, it’s negative in the function. If that makes sense.
In vertex form it means that (3,4) will be
a(x-3)^2+4
