You could be intimidated by graphs but I don’t think there’s any need. You just need to learn a few definitions and practice a few techniques to pick up some relatively easy marks.

**Line Segments and Mid-points**

A graph paints a thousand words:

In examples like the one above you can just use common sense to find the mid-point of a line segment like the one above but you can calculate the mid-point from just the co-ordinates of a line segment with this formula:-

So, for example a line segment AB has coordinates

A: (2, 10)

B: (10, 16)

What is the mid=point?

Using the formula from above, we have

Midpoint = ((2+10)÷2), ((10+16)÷2)

= (6, 13)

You can see this on a graph:-

**Plotting Straight-Line Graphs**

When you plot a **linear function **on a graph you get a straight line. A linear function is usually expressed in the format y= mx + b.

You can plot a linear function by feeding in values of ‘X’ and calculating ‘Y’. In theory, because a linear function will result in a straight line you only need two sets of coordinates. Normally you will be asked to calculate a few sets of coordinates in a table and then plot the line.

For example; draw the graph of y = 3x + 3 for values of x from –3 to +3

Just 3 simple steps; draw up a table, calculate the values of y and plot the graph:

Table of Values and Graph of Linear Function y = 3x + 3

To be continued…