Do NowFind the slope of the line passing through the

given points.

1) ( 3, – 2) and (4, 5)

2) (2, – 7) and (– 1, 4)

What is the slope of a horizontal line?

The line doesn’t rise!

m 0

number0

All horizontal lines have a slope of 0.

What is the slope of a vertical line?

The line doesn’t run!

All vertical lines have an undefined slope.

m number

0undefined

Find the slope of the line passing through the two given points.

1) (-3,5) and (-3,1)

2) (4, 6) and (1,6)

The line passing through the points (2, 8) and (6, k)

has a slope of . Find k. 4

1

The line passing through the points (5, – 8) and (3, a)

has a slope of 4. Find a.

Slope – Intercept Form

y = mx + b

m represents the slope of the lineb represents the y-intercept

The y-intercept is the point where the line crosses the y-axis.

Write a slope-intercept equation of the line with the given slope and y-intercept.

1) m = 2, b = – 3

2) m = – 4, b = 5

3) m = , b = 04

1

4) Write the equation of a line that has a y-intercept of -3 and a slope

of -4.1. y = -3x – 4

2. y = -4x – 3

3. y = -3x + 4

4. y = -4x + 3

Find the slope and y-intercept for each line.

5) y = 4x – 1

6) y = – x + 3

7) y = 2x – 5

8) Find the slope and y-intercept of y = -2x + 4

1. m = 2; b = 4

2. m = 4; b = 2

3. m = -2; b = 4

4. m = 4; b = -2

Writing Equations From The Graph

Use the graph to find the slope and y-intercept.

1) Use two points to find the slope.

2) Look where the line crosses the y-axis.

3) Substitute into y = mx + b

1) Write the equation of the line.

2) Write the equation of the line.