1. Starter Activity: Guess the Rule
y = mx + c
Starter Activity: Guess the Rule x y x y 2 -2 1 4 1 1 2 6 2 4 3 8 3 7 -4 6 -4
-14
y = 2x + 2
y = 2x + 1

2. Starter Activity: Guess the Rule
y = mx + c
Starter Activity: Guess the Rule x y x y 3 33 2 10 4 43 4 18 5 53 6 26 6 63 8 34 -4
-37 -4
-14
y = 10x + 3
y = 4x + 2

3. Starter Activity: Guess the Rule
y = mx + c
Starter Activity: Guess the Rule x y x y 20 96 2 21
101 1 22
106 2 -2 23
111 3 -4 -4 24 -4 10
y = 5x - 4
y = -2x + 2

4. OBJECTIVE: By the end of the lesson you should…
…be able to …
… find the equation for any linear graph from the diagram
(All pupils)
… find the equation of any line given any two points on the line
(Most pupils)
… use these skills to interpret real life problems
(Some pupils)

5. Straight Line Graphs (y = mx + c)1 2 3 4 5 6 7 8 9 10 -9 -8 -7 -6 -5 -4 -3 -2 -1
-10 x y
Straight Line Graphs (y = mx + c)
m gives the gradient of the line and c gives the y intercept.
All straight line graphs are of the form y = mx + c
ch y = 2
ch x = 1
y = 2x + 3
y intercept = 3
The gradient is defined as the Change in y Change in x

6. Straight Line Graphs (y = mx + c)1 2 3 4 5 6 7 8 9 10 -9 -8 -7 -6 -5 -4 -3 -2 -1
-10 x y
Straight Line Graphs (y = mx + c)
m gives the gradient of the line and c gives the y intercept.
All straight line graphs are of the form y = mx + c
ch y = 3
y = 3x - 4
ch x = 1
The gradient is defined as the Change in y Change in x
y intercept = -4

7. Straight Line Graphs (y = mx + c)1 2 3 4 5 6 7 8 9 10 -9 -8 -7 -6 -5 -4 -3 -2 -1
-10 x y
Straight Line Graphs (y = mx + c)
m gives the gradient of the line and c gives the y intercept.
All straight line graphs are of the form y = mx + c
y = ½x + 1
ch y = 1
ch x = 2
y intercept = 1
The gradient is defined as the Change in y Change in x

8. Straight Line Graphs (y = mx + c)1 2 3 4 5 6 7 8 9 10 -9 -8 -7 -6 -5 -4 -3 -2 -1
-10 x y
Straight Line Graphs (y = mx + c)
m gives the gradient of the line and c gives the y intercept.
All straight line graphs are of the form y = mx + c
The gradient is defined as the Change in y Change in x
ch y = 1
ch x = 3
y intercept = -5

9. Straight Line Graphs (y = mx + c)1 2 3 4 5 6 7 8 9 10 -9 -8 -7 -6 -5 -4 -3 -2 -1
-10 x y
Straight Line Graphs (y = mx + c)
m gives the gradient of the line and c gives the y intercept.
All straight line graphs are of the form y = mx + c
ch y = 3
ch x = 4
y intercept = 2
The gradient is defined as the Change in y Change in x

10. Straight Line Graphs (y = mx + c)1 2 3 4 5 6 7 8 9 10 -9 -8 -7 -6 -5 -4 -3 -2 -1
-10 x y
Straight Line Graphs (y = mx + c)
m gives the gradient of the line and c gives the y intercept.
All straight line graphs are of the form y = mx + c
y intercept = 3
ch y = 4
ch x = 5
The gradient is defined as the Change in y Change in x

11. Key Questions: Find the formulae for these Real Life Problems
(1) A taxi firm has a formula for working out fares
It is in the form P=mN + c P=Price N = No. miles A 0 mile journey costs £2 A 2 miles journey costs £6
(2) A taxi firm has a formula for working out fares
It is in the form P=mN + c P=Price N = No. cards 60 cards cost £ cards cost £255
Hint: If it helps then quickly sketch the graphs with N going across and P going up

12. OBJECTIVE: Have you met your lesson objectives?
Are you able to …
… find the equation for any linear graph from the diagram
(All pupils)
… find the equation of any line given any two points on the line
(Most pupils)
… use these skills to interpret real life problems
(Some pupils)