1. SWBAT… Write and graph lines in slope-intercept form Thurs, 12/7
Agenda
WU (15 min)
Video on graphing (10 min)
Graphing lines (15 min)
Writing equations of lines in slope-intercept form
Warm-Up: Solve each equation for y:
1.) 2y = 4x + 2
2.) -3y = -9x – 12
3.) 21x – 7y =14
4.) 2y + 26 = -6x
HW5: Writing and graphing equations in slope-intercept form

2. When an equation is in slope-intercept form:
y = mx + b
slope
y-intercept
Now look at the equation below…… 2
What is the slope? ____________ 1
What is the y-intercept? ____________

3. Converting linear equations into Slope-Intercept Form
4 Warm-UP Examples

4. Our main goal is to get the y alone on one side of the equation
Slope intercept form is:
y = mx + b
Our main goal is to get the y alone on one side of the equation

5. Example 1 - convert into Slope-Intercept Form
(divide both sides by 2 to get y alone)
(now simplify all fractions) 2 1
What is the slope? _____
What is the y-intercept? ______

6. Example 2 – Convert to Slope-Intercept Form
-3y = -9x – 12
Step 1: divide both sides by -3 to get y alone
Step 2: Simplify all fractions
Step 3: Write your equation in y = mx + b
What is the slope? ____________
What is the y-intercept? ____________

7. *** Check Your Answer ***
-3y = -9x – 12
(divide both sides by -3 to get y alone)
(now simplify all fractions)
-3y = -9x – 12
y = 3x + 4
Wow, you’re good at this!!
Slope = 3
Intercept = 4

8. Example 3: Convert to Slope-Intercept Form
21x – 7y =14
(subtract both sides by 21x)
(now divide both sides by -7)
-7y = -21x + 14
(simplify all fractions)
y = 3x – 2
What is the slope? _________
What is the y-intercept? ________

9. Example 4: Convert to Slope-Intercept Form
2y + 26 = -6x
Step 1: Subtract both sides by 26
Step 2: Divide both sides by 2 to get y by itself
Step 3: Simplify all fractions
What is the slope? ____________
What is the y-intercept? ____________

10. *** Check Your Answer ***
2y + 26 = -6x
(subtract both sides by 26)
(now divide both sides by 2
2y = -6x – 26
(simplify all fractions)
y = -3x – 13
You are a math wizard!

11. Families of Linear Graphs

12. Graph 3y - 6 = 2x y = 2/3x + 2 y = 2/3x + 2 Step 1: Solve for y y
Step 2: Look at the y-intercept and plot
where the graph crosses the y-axis.
Step 3: Use the slope (rise/run) to determine the next point and plot.
Slope = 2/3 = 2/3 x
3y – 6 = 2x
3y = 2x + 6
y = 2/3x + 2
Step 4: Draw a line through both points. Be sure to extend the line and put arrows at both ends. (Use a ruler!)
Step 5: Label your line

13. Graph y = 2x + 1 Step 1: Solve for y y
Step 2: Look at the y-intercept and plot
where the graph crosses the y-axis.
y = 2x + 1
Step 3: Use the slope (rise/run) to determine the next point and plot.
Slope = 2 = 2/1 x
Step 4: Draw a line through both points. Be sure to extend the line and put arrows at both ends. (Use a ruler!)
Step 5: Label your line

14. Graph y = -x - 2 Step 1: Solve for y y
Step 2: Look at the y-intercept and plot
where the graph crosses the y-axis.
y = -x – 2
Step 3: Use the slope (rise/run) to determine the next point and plot.
Slope = -1 = -1/1 x
Step 4: Draw a line through both points. Be sure to extend the line and put arrows at both ends. (Use a ruler!)
Step 5: Label your line