Quandaries
and Queries 

12 grade, algebra II Given
the vertex (4, 2) I'm subbing for a math class, and just can't remember. Thanks for any help you can offer. 

Hi Delores, First plot the two points (4,2) and (0,6) on the plane and then draw a rough sketch of what the parabola. This is a parabola that opens downward. I know that the "standard" parabola with vertex at (0,0) and which opens downward has equation
The parabola you want is shifted 4 units to the right so the "x" factor should be (x  4). The graph is then shifted up or down (in this case down) and then scaled (either expanded or contracted) to give the parabola you want. Hence I know that the equation is
Now you can determine a and b since the parabola passes through (4,2) and (0,6).
so b = 2, and
so a = ^{1}/_{4}. I don't know what detail you require to actually answer the question. It may be that the sketch at the beginning is enough to see that the parabola does not cross the xaxis. Penny


