In the previous section we looked at modifying equations for graphs to get them into the form

In order to plot linear graphs, we sub a few different

*y*= m*x*+ c. One reason for doing this is so that we can quickly see the gradient (the value of m) and the*y*intercept (the values of c) for the graph. A second reason for getting graphs into the form*y*= m*x*+ c is because graphs are considerably easier to plot/ find the coordinates when they are in this form.

In order to plot linear graphs, we sub a few different

*x*values into the equation to find the respective*y*values. This gives us the coordinates, which we can then plot on a graph. We then draw a line through all of the coordinates; we need to continue the line past the end coordinates rather than ending the line at the coordinates.**Plotting Example 1**

Plot the equation

*y*= 2

*x*– 4.

I am going to sub 5 different

*x*values into the table. Every table that we use will have the rows “

*x*value”, “

*y*value” and “coordinates”. The other rows in the table will depend on the equation that we are plotting. We are plotting

*y*= 2

*x*– 4. We are going to have another row for each of these components. Therefore, we will have a row for 2

*x*, which will be where we multiply the

*x*value by 2. The values along this row will be different because the value of 2

*x*is dependent on the value of

*x*that we are subbing in. The next row will be -4, which will be the same across the whole row.

We then find the

*y*value by adding the value in the 2

*x*row to the value in the -4 row. To find the coordinates, we take the

*x*value that we subbed in and the

*y*value that we got out.

We plot the coordinates that are given at the bottom of the table on a graph and draw a line through the point (it is important that we continue the line through the start and end of the points rather than stopping on the points that are furthest out).

**Plotting Example 2**

Plot the equation

*y*= -3

*x*+ 3.

Like the question before, I am going to be using the table to find a few coordinates for this graph. We will have the standard 3 rows in the table; “

*x*value”, “

*y*value” and “coordinates”. The other rows in the table will depend on the equation that we are plotting. I am plotting

*y*= -3

*x*+ 3, which means that I will have a row -3

*x*and +3. The fill out table is given below (the video gives a longer explanation as to how the values were found.

We plot the coordinates at the bottom of the table and draw a line that passes through and continues through all of the points. The graph is plotted below.