1. Warm-up 1. Graph 3x - 2y = 4 and find the x and y intercepts.
October 6, 2011 At the end of today, you will be able to: Find and use the slope of a line. Graph parallel and perpendicular lines.
Warm-up
1. Graph 3x - 2y = 4 and find the x and y intercepts.
2. Do the points listed below make a function?
{(-3, 4), (2, 4), (-2, 0), (-3, 1)}
3. Solve |2x – 5| - 8 =
HW 2.3: Pg #15-27odds, 31, Show Work! Quiz Tuesday!

2. Check HW 2.2: Pg. 66 #16-22 even, 30, 33, 36, 40-44 even, 53, 54
16. No (6, 0), (0, -2)
18. No (5, 0), (0, 2)
20. Yes (1/2, 0), (0, -2)
22. No °C
30. x – 7y = km
A = 1, B = -7, C = 2
33. x + y = 12,
A = 1, B = 1, C = 12
36. y = 40
A = 0, B= 1, C = 40

3. What do you remember about the slope of a line?
“rise over run”
Slope formula:
Change of Y over the change of X

4. Let’s go back to Algebra 1: Think of 2 ways to find the slope of the line below:
1st way: Find two points on the line and count the “rise over run”.
rise
run
2nd way: Use

5. Find the slope of the line using the formula, then graph the two points to check your answer.
1. (-2, -2), (3, 3) (0, 3), (3, 0)
Positive Slope
Negative Slope

6. Find the slope of the line using the formula, then graph the two points to check your answer.
1. (-3, 2), (3, 2) (-2, 3), (-2, 2)
Zero Slope
Undefined Slope

7. How do you know if the lines are parallel?
Use a graphing calculator to graph the following lines on the same graph:
, ,
What determines parallel lines?
Name another line that is parallel to the lines above?
The SAME SLOPE!

8. How do you know if the lines are perpendicular?
1. Graph the following lines on the same graph:
2. Clear the last graphs, and graph these:
What do the slopes have to be to be perpendicular?
OPPOSITE RECIPROCAL SLOPES

9. Graphing a line that is parallel to another line.
y-int
Example 1:
Graph the line that passes
through the point (-4,-1),
parallel to a line whose
slope is 3.
How would you write the
equation of this line?
Parallel = same slope
(-4,- 1)
y = 3x + 11

10. Try a perpendicular slope!
Graph the line that passes through (-3, 1) that is perpendicular to a line with a slope of .
*Don’t forget it’s the “opposite reciprocal”
Write the equation of the line.

11. Classwork 2.3: Will be graded!
On a piece of graph paper:
Graph the line that passes through the point (1, 2) and is parallel to a line with a slope of -2.
2. Find the slope of a line that passes through (-4, 2) and (-6, 3)
3. If f(x) = 2x3 – 4x, find
4. Is y = 2x2 a function? Is it linear? Explain your answers.