Alady has 5 kids . one name is january , one name is february , one name is march , one name is april , what is the name of the 5th child .

The given data strongly suggests that the 5th child MIGHT be named 'May',
but really there's no way to know.  We have no reason to assume that the lady
continued the same naming tradition that she established with her first four
children.  For all we know, with four children in the house, she might have
named the 5th one "Enough Already!". 

F(x)=x^2+6x+9. This is the answer you are looking for using the vertex and another point on the graph.