How to find

the equation

of a line.

Equations of lines start with y =

Equations of lines start with y =

Next comes the slope (slopes are fractions)

Equations of lines start with y =

Next comes the slope (slopes are fractions)

Last is the y-intercept.

(the point where the line crosses the y-axis)

Name this line’s equation.

.A.B

.A.B

This line

is going uphill

so the slope is

positive.

.A.B

To get from point

A to point B, go

up 2 and right 2

so this line’s slope

is or 1.2

2

This line

crosses at (0,2)

so the y-intercept

is = to 2.

.A.B

.A.B

This line’s equation is

y = slope = 1 and y –int = 2

.A.B

y = 1slope = 1 and y –int = 2

.A.B

y = 1xslope = 1 and y –int = 2

.A.B

This line’s equation is

y = 1x +2slope = 1 and y –int = 2

Name this line’s equation.

.C

.D

.C

.D

This line

is going downhill

so the slope is

going to be

negative.

.C

.D

To get from point

C to point D, go

down 6 and right 3

so this line’s slope

is or -2.3

6

.C

.D

This line

crosses at (0,4)

so the y-intercept

is = to 4.

.C

.D

We have all the parts

to name this line.

.C

.D

y =

slope = -2 and y-int = 4

.C

.D

y = -2

slope = -2 and y-int = 4

.C

.D

y = -2x

slope = -2 and y-int = 4

.C

.D

The line’s equation is

slope = -2 and y-int = 4

y = -2x + 4

Name this line’s equation.

. J

. K

. J

. KThis line is going

uphill so the slope

will be positive.

. J

. KTo get from point J

to point K, go

up 5 and right 3

so this line’s slope

is .3

5

. J

. KThis line

crosses at (0,-4)

so the y-intercept

is = to -4.

. J

. KWe have all the parts

to name this line.

. J

. Ky =

Slope = and y-int = -4

3

5

3

5

. J

. Ky = x

Slope = and y-int = -4

3

5

3

5

. J

. Ky = x - 4

Slope = and y-int = -4

3

5

3

5

The line’s equation is

Name this lines equation.

. L . M

. L . MThis line is going

uphill so the slope

will be positive.

. L . MTo get from point L

to point M, go

up 1 and right 2

so this line’s slope

is .2

1

. L . MThis line

crosses at (0,2)

so the y-intercept

is = to 2.

. L . MWe have all the parts

to name this line.

. L . M y =Slope = and y-int = 2

2

1

. L . M y =Slope = and y-int = 2

2

12

1

. L . M y = xSlope = and y-int = 2

2

12

1

. L . M y = x + 2Slope = and y-int = 2

2

12

1

The line’s equation is

Name this line’s equation.

. Q . R

. Q . R

Slope =5

1

. Q . R

Slope =

y- int = -3

5

1

. Q . R

The line’s equation is

y = x - 35

1

Name this line’s equation.

. S. T

. S. T

Slope = 3

2

. S. T

Slope =

y-int = 23

2

. S. T

The line’s equation is

y = x +23

2

Name this line’s equation.

. U

. V

. U

. V

Slope = 1

6

. U

. V

Slope =

y-int = +5 1

6

. U

. V

The line’s equation is

y = -6 x + 5

. W

. X

Name this line’s equation.

. W

. X

slope = 5

7

. W

. X

slope =

y-int = 4 5

7

. W

. X

The line’s equation is

y = x + 45

7

. Y

. Z

Name this line’s equation.

. Y

. Z

Slope = 3

4

. Y

. Z

Slope =

y-int = 0 3

4

. Y

. Z

The line’s equation is

y = x + 03

4