CPM Homework Banner

Write an equation for the curve shown below. Is it a function? Justify your answer. 

Curved graph, opens up, with vertex at the point (3, comma 3), & additional points at  (7, comma 5), & (negative 1, comma 5).

What parent graph does this look similar to?
What would the equation be?
And how do you determine if something is a function?

One possible answer is 

Is this a function?