Katie is finding the standard form of the conic parabola. State her mistake by giving the correct vertex.
Y=X^2+6X+4
Y=X^2+6X+9+4
Y=(X+3)^2+4

Question

Katie is finding the standard form of the conic parabola. State her mistake by giving the correct vertex.   
Y=X^2+6X+4
Y=X^2+6X+9+4
Y=(X+3)^2+4

whpalmer4 · Answer

You can do this a number of different ways.  As the parabola's equation is already in the form $y = ax^2+bx+c$, you can determine the vertex x-coordinate directly by evaluating $x = -b/2a$, then determine the y-coordinate by evaluating y at that value of x.

Another approach, probably the one intended by the problem's author, would be to complete the square correctly.  The error made here is that something is added to one side of the equation but not the other.