Graphing Parabolas

The parabola described by the equation y = ax² + bx + c can be quickly graphed by locating the vertex, the y-intercept and determining whether the parabola opens upward or downward.

The vertex is located at the x value -b/2a.
The y value of the vertex is obtained by simply plugging that x value into the function.
The y-intercept is at c.
If a > 0 then the parabola opens upward and if a < 0 the parabola opens downward.

If you are familiar with this technique, go ahead and try this problem. Graph y=3x² + 6x + 1.

How about an example worked out step by step? Here are problems using these steps to graph parabolas. Want to see some examples of real parabolas?

1.	Click on the vertex location.
2.	Click on the y-intercept location.
3.	Click above(below) the vertex to open up(down).