1. Chapter 5.1

2.  Lesson Objective: NCSCOS 4.01 – Students will know how to find the slope of a line  Students will know how to find the equation of a line given 2 points

3.  Example 1: Find the equation of a line that passes through the points (3, 5) and (6, 2)  The equation of a line is:  We always have to find the slope first!

4.  The equation to find slope is:  In order to find slope, we’re going to need to ordered pairs (points)

5.  Find the slope of the line using the two points (3, 5) and (6, 2)  To solve this problem, we have to label our two points.  It doesn’t matter which point you label x1 and which one x2

6.  Plug the points into the slope equation

7.  Simplify the top and the bottom  Simplify the fraction

8.  m = -1, so the slope for these two points is -1

9.  Once you know slope, plug it into the equation:  To find b we have to plug in one of the points  It doesn’t matter which point, if they are both on the same line, they will both work for this equation

10.  Plug in one of the points Multiply on the right side Add 3 to both sides Plug b back into the equation

11. 1. (1, 3), (2, 7) 2. (6, 3), (7, -4) 3. (6, -2), (5, -4) 4. (7, -4), (4, 8) 5. (12, 2), (-6, 5) Find the equation using the following points

12. 1. (1, 3), (2, 7) 2. (6, 3), (7, -4) 3. (6, -2), (5, -4) 4. (7, -4), (4, 8) 5. (12, 2), (-6, 5) Find the equation using the following points

13.  Example: Find the equation of the line A.  In order to find slope, you need two points  Find two points on the line  Plug the points into the slope equation A (-1, -3) (1, 1)

14.  Label the points and write the equation (-1, -3) (1, 1) (-1, -3) x 1, y 1 x 2, y 2

15.  Plug the slope into a new equation Plug in one of the points Multiply on the right side Subtract 2 from both sides Plug b back into the equation

16. 1. Find the equation of Line A 2. Line B 3. Line C 4. Line D D C B A

17. 1. Find the equation: (5, 2), (3, -4) 2. (-1, 6), (7, -10) 3. (0, 2), (1, 7) 4. (-2, -1), (2, 11) 5. (10, -1), (4, 2)

18. 1. Find the equation: (5, 2), (3, -4) y = 3x – 13 2. (-1, 6), (7, -10) y = -2x + 4 3. (0, 2), (1, 7) y = 5x + 2 4. (-2, -1), (2, 11) y = 3x + 5 5. (10, -1), (4, 2) y = -1/2x + 4