2.  So far we know that to the important parts of a line graph are the x-intercept, y-intercept and the gradient, or slope.

3. X - intercept Y-intercept Gradient or slope

4.  y = mx + c is the basic rule for any line graph.  The letter m and x represent different aspects that can be read of a graph

5.  C is the easier of the two letters to work out from a graph.  It is simply the value of the y-intercept. So the point where the graph crosses the y-aixs is the value of c.

6.  Find the value of ‘c’ in the following graphs. -4 -3 -2 -1 1 2 3 4 4321-1-2-3-44321-1-2-3-4 X Y

7.  The letter ‘m’ in y =mx + c represents the gradient or slope of a graph.  M is found by working out the rise of a graph and then the run, or movement across, of the graph.  M = rise run

8. 3 2 1 -2 -3 -3 -2 -1 1 2 3 1. Choose a spot on the graph that sits on a value on a y value 2. State the y-value of this point Y = 0 3. Choose another point on the graph that sits on a y value 4. State the y-value of this point. Y = 2 5. Find the difference between these two points, the rise Rise = 2 – 0 Rise = 2

9. 3 2 1 -2 -3 -3 -2 -1 1 2 3 IMPORTANT: If a graph slants downwards from left to right, then it is actually a drop rather than a rise and you must put a negative (-) in front.

10. 3 2 1 -2 -3 -3 -2 -1 1 2 3 1. Find the points that you would use for the rise 2. Find the x- value of the first point 3. Find the x- value of the second point 4. Find the total movement across, the run X = -2 X = 0 Run = -2 to 0 So total movement across is 2 Run = 2

11. 3 2 1 -2 -3 -3 -2 -1 1 2 3

12.  Now that you know how to find the rise and the run separately, you need to put the two of them together to find the value of m.

13. 3 2 1 -2 -3 -3 -2 -1 1 2 3 1. Find the rise 2. Find the run 3. Solve rise run Rise = 0 to 3 Rise = 3 Run = -1 to 0 Run = 1 m = rise run m = 3 1 m = 3

14. 3 2 1 -2 -3 -3 -2 -1 1 2 3 1.Find the value for c 2.Find the value for m 3.Put the found values into the equation What is the y-intercept? C = -3 What is the gradient? m = 3 2 Put this into the rule… y = 3x – 3 2

15. 3 2 1 -2 -3 -3 -2 -1 1 2 3 3 2 1 -2 -3 -3 -2 -1 1 2 3