Lesson 5.3- Slope Intercept Form, pg. 272

Goals: To write and graph linear equations in slope-intercept form.

To model real-world data with an equation in slope-intercept form.

Slope-Intercept Form

The linear equation y = mx + b is written in slope-intercept form, where m is the slope and b is the y-intercept.

Y = mx + b

slope Y-intercept

Ex. 1: Write an equation given slope and y-intercept

1. slope: 3

y-intercept: -5

2. slope: -3/5

y-intercept: 0

3. slope: 0.5

y-intercept: 7.5

5. slope: 8

y-intercept: -3

4. slope: 4

y-intercept: -2

6. slope: -1

y-intercept: -7

Ex. 2: Write an equation of the line shown in each graph.

1. y

x

5

5

-5-5

2. y

x

5

5

-5-5

3. y

x

5

5

-5-5

Ex. 3: Graph the equation.

1. y = x - 2 y

x

5

5

-5-5

2. y = -x + 2 y

x

5

5

-5-5

3. y = -1/3x - 3 y

x

5

5

-5-5

4. 2x – y = -3 y

x

5

5

-5-5

5. 4x – 3y = 3 y

x

5

5

-5-5

Ex. 3: Write a linear equation in slope-intercept form to model the situation.

1. An auto repair shop charges $50 plus $25 per hour.

Y = mx + b

2. The temperature is 15° and is expected to fall 2° each hour during the night.

Y = mx + b

3. A computer technician charges $75 for a consultation plus $35 per hour.

Y = mx + b