All quadratic graphs have the same form - they look something like this:

For all quadratic graphs, there are** three** things you need to be able to read from the graph: **the roots, the vertex and the y-intercept.**

These can be found at the following places:

**The roots** occur where the graph crosses (or touches) the x-axis. You need to remember that for a quadratic, there could be either two roots(as in the example), one root (if the graph just touches the x-axis) or even zero roots (if the graph is above the x-axis).

**The intercept** occurs where the graph crosses the y–axis.

**The vertex**, also called the turning point, is the lowest (or highest if the quadratic is negative) value of the graph.

**Example:**

Find the significant points on this quadratic graph:

This is just a case of reading them off the graph.

**The roots** are at x = -3 and x = 4

**The intercept** is at y = -12

**The vertex** is a little harder to read as it isn’t exactly on a point. When you get this situation, remember that you will get some leeway.

This point also has to be given as a coordinate as it is not on an axis. (0.5, -12.2)

Time for some questions now.