1. Lesson 5-4 Point-Slope Form Sept. 22, 2014

2. Daily Learning Target I will write and graph linear equations using point-slope form.

3. What is it? y – y 1 = m(x – x 1 ) m = slope (x 1, y 1 ) = a point the line goes through.

4. Here is how it works!!

5. How it works cont.

6. Example 1

7. You Try It

8. Example 2

9. You Try

10. Example 3 What is an equation of the line from the coordinate plane? Steps to think about: Think  --You need the slope m, so start with the slope formula. – Use the given points to find the slope – Use point-slope form – Use either point for (x 1, y 1 ).

12. You Try

13. Example 4 The table shows the altitude of a hot-air balloon during its linear descent. What equation in point-slope form. What does it look like in slope-intercept form? PSF: y – 640 = -2.5(x – 10) SIF: y = -2.5x + 665 Time, x (s)Altitude, y (m) 10640 30590 70490 90440

14. You Try The table shows the number of gallons of water, y, in a tank after x hours. The relationship is linear. What is an equation in point-slope forms that models that data. What does the slope represent? PSF: y – 3320 = 1250(x – 2); The rate at which water is being added to the tank. Time, x (h)Water, y (gal) 23320 34570 57070 810,820

15. Homework Workbook: Page 151 problems 1, 3, 4, 6, 7, 8, 10, 11, 13 Page 153 problems 1-6 ALL