1. Lines from Slope Formula Purpose : Use the slope formula to write equations of lines. Note: We are only dealing with linear functions. © Evergreen Public Schools 9/27/11

2. Learning Target Linear Equations Target 3a I can write the equation of on a line when I am given two points on the line. What do you already know about this?

3. Launch Write the equation of this line.

4. Explore

5. How can we write the equation of the lines that passes through the points: (5, 10), (0, 7) without graphing?

6. Here’s a way Find the slope (5, 10), (0, 7). How many points are on this line? So ( x, y ) can represent another point on the line.

7. Here’s a way Now use the slope formula to find the equation. Replace (5, 10) with ( x, y ) and use the slope you just found.

8. Here’s a way Simplify Multiply to eliminate fractions. 55 x x

9. Here’s a way Simplify How does this equation compare the the equation you write in slide 3?

10. Dyad (or Triad) Check Write the equation of the line with the points. DyadTriad (0, 1) and (4, 5)I and IIII (3, 0) and (9, 4)II and IVII (0, 3) and (4, 5)III

11. Quick Write Describe the process you used to find the equation of the line through two points.

12. 5 3 1 2 4 Learning Target Did you hit the target? Linear Equations Target 3a I can write the equation of on a line when I am given two points on the line. Rate your understanding of the target from 1 to 5.

13. Practice 3.5A Line Through Two Points