1. First let’s review 5.1 y = mx + b
Write the equation in slope-intercept form, given m = 3 ang b = (0,-2)
Example
m = 3, b = (0,-2)
y = mx + b
y = __ x + ___

2. Write the equation of the line in slope-intercept form.
b = (0,1)
y = mx + b

3. Given this equation, what is the slope and y-intercept?
+2x x
3y = 2x + 15
m = 2/3
b = (0,5)

4. Review 5.2 Point-Slope Form

5. Write the equation of the line in point-slope form.
(0,3)
Or you can use any point
(3,2)

6. Given (2,3) and slope = -2, write the equation in SLOPE-INTERCEPT
This is the equation of the line in point-slope form!!
Now leave your
answer in slope-
intercept form.

7. Given (-8,4) and slope = -3/2, write the equation in SLOPE-INTERCEPT
This is the equation of the line in point-slope form!!
Now leave your
answer in slope-
intercept form.

8. 5.3 Writing equations of a line given two points

9. Forms of a linear equation
Slope-intercept Form y = mx + b
Point-Slope Form y – y1 = m(x – x1)

10. If given two points, First, find the slope using the slope formula.
(x1 , y1) and (x2 , y2)
First, find the slope using the slope formula.
Example
contains (5, –8) and (2, 7)
m = 15 –3
m = –5
m = 7 – -8
2 – 5

11. If given two points, Then use the slope and EITHER point to work
like the previous example.
y – y1 = m(x – x1)
y – 7 = – 5(x – 2)
y – 7 = –5x + 10
m = –5,
contains (5, –8) and (2, 7)
y = –5x + 17

12. Writing an Equation Given Two Points
1. Calculate the slope of the line.
2. Select the form of the equation.
a. Slope-intercept form
b. Point-slope form
3. Substitute and/or solve for the selected form.

13. Writing an Equation Given Two Points
Given the two ordered pairs, write the equation of the line in point-slope form.
Calculate the slope. or

14. Writing an Equation Given Two Points in point-slope form:

15. Same example: Writing an Equation Given Two Points in slope-intercept form.
Start by using point-slope form:

16. 2.) Writing an Equation Given Two Points in slope-intercept form.
(-5,7) (2,-7)
Start by using point-slope form:

17. EVERY ONE GET A COMMUNICATOR:
WITH A BLANK SIDE!!

18. 3.) Writing an Equation Given Two Points in slope-intercept form.
(2,0) (-2,6)
Start by using point-slope form:

19. 4.) Writing an Equation Given Two Points in slope-intercept form.
(10,-5) (8,4)
Start by using point-slope form:

20. 5.) Writing an Equation Given Two Points in slope-intercept form.
(6,5) (-3,5)
Start by using point-slope form:
Horizontal line

21. 6.) Writing an Equation Given Two Points in slope-intercept form.
(-2,-4) (-4,8)
Start by using point-slope form:

22. 7.) Writing an Equation Given Two Points in slope-intercept form.
(-6,6) (9,1)
Start by using point-slope form:

23. NOW WHAT IF I GAVE YOU A GRAPH, TELL ME THE EQUATION OF THE LINE:
WHAT’S THE MAJOR DIFFERENCE BETWEEN THESE TWO GRAPHS:
So creating an equation using slope-intercept form would NOT work!!!
The one on the right does not
have a CLEAN y-intercept!!

24. Create the equation of the line using two points on the line:
(-3,4) (5,8)