The answer depends on what information you have and what form you are checking.
The functional form of a parabola is y = ax2+ bx + c where a, b and c are real and a >0. If that is the case then, functionally it is a parabola.
The graph of a parabola has a single turning point and is symmetric about its axis. But that is not enough. The graph of y = ax4+ bx2 + c or y = ax6+ bx3+ c have similar shapes but they are not parabolas.
Find the axis. This should be easy because the parabola is symmetric about its axis. Draw a number of lines parallel to the axis. Where they meet the parabola, reflect them. These reflected lines should all meet at the same point which is the focus of the parabola.
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The vertex would be the point where both sides of the parabola meet.
A parabola is NOT a point, it is the whole curve.
The line of symmetry located on a parabola is right down the center. A parabola is a U shape. Depending on the direction of the parabola it either has a x axis of symmetry or y axis of symmetry. You should have two equal sides of the parabola.
To find the value of a in a parabola opening up or down subtract the y-value of the parabola at the vertex from the y-value of the point on the parabola that is one unit to the right of the vertex.
A parabola has a single focus point. There is a line running perpendicular to the axis of symmetry of the parabola called the directrix. A line running from the focus to a point on the parabola is going to have the same distance as from the point on the parabola to the closest point of the directrix. In theory you could look at a parabola as being an ellipse with one focus at infinity, but that really doesn't help any. ■