0 1 2 3 4 5 6 7 8 9 10-9 -8 -7 -6 -5 -4 -3 -2 -1-10 x

y

1

2

3

4

5

6

7

8

9

10

-1

-2

-3

-4

-5

-6

-7

-8

-9

-10

Straight Line Graphs

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

rise/run

rise = 2

run = 1

y intercept = 3

y = 2x + 3

0 1 2 3 4 5 6 7 8 9 10-9 -8 -7 -6 -5 -4 -3 -2 -1-10 x

y

1

2

3

4

5

6

7

8

9

10

-1

-2

-3

-4

-5

-6

-7

-8

-9

-10

Straight Line Graphs

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

rise/run

rise = 3

run = 1

y intercept = -4

y = 3x - 4

0 1 2 3 4 5 6 7 8 9 10-9 -8 -7 -6 -5 -4 -3 -2 -1-10 x

y

1

2

3

4

5

6

7

8

9

10

-1

-2

-3

-4

-5

-6

-7

-8

-9

-10

Straight Line Graphs

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

rise/run

rise = 1run = 2

y intercept = 1

y = ½x + 1

0 1 2 3 4 5 6 7 8 9 10-9 -8 -7 -6 -5 -4 -3 -2 -1-10 x

y

1

2

3

4

5

6

7

8

9

10

-1

-2

-3

-4

-5

-6

-7

-8

-9

-10

Straight Line Graphs

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

rise/runrise = 1

run = 3

y intercept = -5

1y= x- 5

3

0 1 2 3 4 5 6 7 8 9 10-9 -8 -7 -6 -5 -4 -3 -2 -1-10 x

y

1

2

3

4

5

6

7

8

9

10

-1

-2

-3

-4

-5

-6

-7

-8

-9

-10

Straight Line Graphs

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

rise/run

rise = 3

run = 4

y intercept = 2

3y= x +2

4

Consider the straight lines shown below:

(a) (c)(b) (d) (e)

Can you split the lines into two groups based on their gradients ?

Lines (a) (c) and (d) slope upwards from left to right.

Lines (b) and (e) slope downwards from left to right.

Positive gradient

Negative gradient

0 1 2 3 4 5 6 7 8 9 10-9 -8 -7 -6 -5 -4 -3 -2 -1-10 x

y

1

2

3

4

5

6

7

8

9

10

-1

-2

-3

-4

-5

-6

-7

-8

-9

-10

Straight Line Graphs

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

rise/run

rise = 4

run = 5

y intercept = 3

4y=- x +3

5

1. y = 2x + 3

2. y = 3x – 5

3. y = -x + 6

4. Y = ½x –2

5. Y = - 4x –9

6. y = ¾x 0 1 2 3 4 5 6 7 8 9 10-9 -8 -7 -6 -5 -4 -3 -2 -1-10 x

y

1

2

3

4

5

6

7

8

9

10

-1

-2

-3

-4

-5

-6

-7

-8

-9

-10

Determine the equations of the following lines

1

2

3

4

5

6