1. Warm Up

2. To be able to write a linear equation.
Today’s Objective
To be able to write a linear equation.

3. y = mx + b Slope-intercept form of the equation:
Recall #1
Slope-intercept form of the equation:
y = mx + b
m is slope and b is the y-intercept.

4. Recall #1
y = mx + b
y = 3x + 2
3 is slope and 2 is the y-intercept.

5. Y = 3x + 2
Slope = 3/1 Y
y-intercept X

6. Recall #2
Slope Formula:
m = y2 - y x2 - x1

7. (1, 4) and (2, 3) (x1, y1) & (x2, y2) m = 3 - 4 2 - 1 Recall #2
Slope Formula:
m = y2 - y x2 - x1

8. Recall #2
m =
m =
m = -1

9. Write a linear Equation
If f(2) = 5 and f(6) = 3
f(2) = 5 when x =2 & y = (2,5)
f(6) = 3 when x = 6 & y = (6,3)

10. (2,5) & (6,3)
When x = 2, f(x) = 5
f(x)
When x = 6, f(x) = 3 X

11. (2, 5) and (6, 3) (x1, y1) & (x2, y2) m = 3 - 5 6 - 2
Step 1 find the slope
(2, 5) and (6, 3)
(x1, y1) & (x2, y2)
m =
Slope Formula:
m = y2 - y x2 - x1

12. Step 1 find the slope
m =
m =
m = -1/2

13. y = mx + b (2,5) and (6,3) 5 = -1/2(2) + b 5 = -1 + b 6 = b
Step y = mx + b
y = mx + b
(2,5) and (6,3)
5 = -1/2(2) + b
5 = -1 + b
6 = b

14. y = -1/2x + 6 is the equation of the line.
Finish
If m = -1/2 and b = 6, then:
y = -1/2x + 6 is the equation of the line.

15. Y = -1/2x + 6
f(x) X

16. Your Turn Write an equation of the line for: f(2) = -2 and f(-4) = 1
Step 1 find the slope
Step 2 use y = mx + b to find the b value.

17. f(2) = -2 and f(-4) = 1 (2, -2) and (-4, 1) Slope = y2 - y1 x2 - x1
Step 1 find the slope
f(2) = -2 and f(-4) = 1
(2, -2) and (-4, 1)
Slope = y2 - y x2 - x1

18. (2, -2) and (-4, 1) Slope = 1 - -2 -4 - 2 Slope = 3 -6
Step 1 find the slope
(2, -2) and (-4, 1)
Slope =
Slope =
m = -1/2

19. y = mx + b (2,-2) and (-4,1) -2 = -1/2(2) + b -2 = -1 + b -1 = b
Step y = mx + b
y = mx + b
(2,-2) and (-4,1)
-2 = -1/2(2) + b
-2 = -1 + b
-1 = b

20. y = -1/2x + -1 is the equation of the line.
Finish
If m = -1/2 & b = -1, then:
y = -1/2x + -1 is the equation of the line.

21. Classwork
See Side Board