1. Straight Lines
Objectives:
D Grade Solve problems involving graphs, such as finding
where the line y = x +3 crosses the line y = 2
C Grade Find the mid-point of a line segment, given two
pairs of coordinates on the line
Prior knowledge: Recognise and draw straight lines from
equations of the form y = mx + c

2. Find the coordinates where the line y = 2 crosses x = 3
Straight Lines
Find the coordinates where the line y = 2 crosses x = 3 1 2 3 4 5 6 7 8 9 10 -9 -8 -7 -6 -5 -4 -3 -2 -1
-10 x y
Draw the line y = 2
Draw the line x = 3
The lines cross at (3,2)
The point of intersection

3. Straight Lines
Now do these:
Find the points of intersection of the following pairs of lines
(use the grids on the paper supplied):
1. x = 1, y = -2
2. x = 4, y = -6
3. x = -6, y = -4
4. x = -6, y = 3
5. x = 7, y = 8
6. y = 0, x = 3
7. y = 5, x = -5
8. y = -2, x = -9
9. y = 1, x = 0
10. y = 10, x = 10
(1, -2)
(4, -6)
(-6, -4)
(-6, 3)
(7, 8)
(3, 0)
(-2, 5)
(-9, -2)
(0, 1)
(10, 10)
Can you see how to find the point of intersection without drawing
the lines?

4. Find the coordinates where the line y = x + 1 crosses y = -2x - 2
Straight Lines
Find the coordinates where the line y = x + 1 crosses y = -2x - 2 y
Draw the line y = x + 1 10 9
Draw the line y = -2x - 2 8 7
The lines cross at (-1,0) 6 5 4 3 2 1 x 1 2 3 4 5 6 7 8 9 10 -9 -8 -7 -6 -5 -4 -3 -2 -1
-10 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10

5. Straight Lines
Now do these:
Find the points of intersection of the following pairs of lines
(use the grids on the paper supplied):
1. y = x + 1, y = -x - 1
2. y = 2x - 1 , y = -3x + 9
3. y = 2x - 5 , y = x - 3
4. y = 3x - 4, y = -x + 4
5. y = 2x + 4 , y = -2x - 8
(-1, 0)
(2, 3)
(2, -1)
(2, 2)
(-3,-2)

6. (2, 3) (-1, 0) (2, 2) (2, -1) y = -x + - 1 y = - 3x + 9 y = x + 1 10 9 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10 10 9 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10
y = -x + - 1
(2, 3)
(-1, 0)
y = - 3x + 9
y = x + 1
y = 2x - 1 10 9 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10 10 9 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10
y = x + 3
(2, 2)
y = x - 3
(2, -1)
y = 3x - 4
y = 2x - 5

7. 10 9 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10
Worksheet 1 10 9 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10 10 9 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10 10 9 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10

8. 10 9 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10
Worksheet 2 10 9 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10 10 9 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10 10 9 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10