5 6 SlopeIntercept Form Warm Up Find each

5 -6 Slope-Intercept Form Warm Up Find each y-intercept. 1. y = 3 x + 2 2 2. 5 x – 3 y = 12 – 4 Find each slope. 3. Holt Algebra 1 4. 6 x + 2 y = 6 – 3

5 -6 Slope-Intercept Form Objectives Write a linear equation in slope-intercept form. Graph a line using slope-intercept form. Holt Algebra 1

5 -6 Slope-Intercept Form You have seen that you can graph a line if you know two points on the line. Another way is to use the point that contains the y-intercept and the slope of the line. Holt Algebra 1

5 -6 Slope-Intercept Form Directions: Graph the line given the slope and y-intercept. Holt Algebra 1

5 -6 Slope-Intercept Form Example 1 slope = 2, y-intercept = – 3 Step 1 The y-intercept is – 3, so the line contains (0, – 3). Plot (0, – 3). Run = 1 • Rise = 2 Step 2 Slope = Count 2 units up and 1 unit right from (0, – 3) and plot another point. Step 3 Draw the line through the two points. Holt Algebra 1 •

5 -6 Slope-Intercept Form Example 2 y intercept = 4 Rise = – 2 Step 1 The y-intercept is 4, so the line contains (0, 4). Plot (0, 4). Step 2 Slope = y • • • Run = 5 Count 2 units down and 5 units right from (0, 4) and plot another point. Step 3 Draw the line through the two points. Holt Algebra 1 •

5 -6 Slope-Intercept Form Example 3 slope = 4; y-intercept = Run = 1 Rise = 4 Step 1 The y-intercept is , so the line contains (0, ). Plot (0, ). Step 2 Slope = Count 4 units up and 1 unit right from (0, ) and plot another point. Step 3 Draw the line through the two points. Holt Algebra 1 • •

5 -6 Slope-Intercept Form Example 4 slope = , y-intercept = 1 Step 1 The y-intercept is 1, so the line contains (0, 1). Plot (0, 1). Rise = – 2 Step 2 Slope = Count 2 units down and 3 units right from (0, 1) and plot another point. • Step 3 Draw the line through the two points. Holt Algebra 1 • Run = 3

5 -6 Slope-Intercept Form In this form, you can immediately see the slope and y -intercept. Also, you can quickly graph a line when the equation is written in slope-intercept form. Directions: Write the equation that describes the line in slope-intercept form. Holt Algebra 1

5 -6 Slope-Intercept Form Example 5 slope = ; y-intercept = 4 y = mx + b Substitute the given values for m and b. y= Simply if necessary. Holt Algebra 1 x+4

5 -6 Slope-Intercept Form Example 6 slope = – 9; y-intercept = Holt Algebra 1 y = mx + b Substitute the given values for m and b. y = – 9 x + Simply if necessary.

5 -6 Slope-Intercept Form Example 7 slope = 3; y-intercept = y = mx + b Substitute the given values for m and b. Simply if necessary. Holt Algebra 1

5 -6 Slope-Intercept Form Example 8 slope = ; y-intercept = – 6 y = mx + b Substitute the given values for m and b. Simply if necessary. Holt Algebra 1

5 -6 Slope-Intercept Form Lesson Summary Write the equation that describes each line in the slope-intercept form. 1. slope = 3, y-intercept = – 2 y = 3 x – 2 2. slope = 0, y-intercept = y= Holt Algebra 1