1. Lesson 1.3 Algebra 3 Objectives:
Student
Algebra 3
Lesson 1.3
Objectives:
SSBAT write the equation of a line given the slope and y-intercept.
SSBAT write the equation of a line given the slope and a point on the line.
SSBAT write the equation of a line given 2 points.
Standards: M11.D.3.2.2

2. Warm-Up 1.3
Solve each for y.
6x – 2y = x + 5y = 7x – 2y + 14

3. Writing an Equation given the Slope and Y-intercept
 Substitute the slope and y-intercept into the equation y = mx + b for m and b

4. Write the equation of each line with the given slope and y-intercept
Write the equation of each line with the given slope and y-intercept. (y = mx + b)
Slope is and y-intercept is 11

5. 2. Slope is -9 and y-intercept is -4

6. 3. Slope is 0 and y-intercept is 12

7. y - y1 = m(x - x1) Point-Slope Form of an Equation of a Line
Used to write the equation of a line given
1) A point on the line and the slope
2) 2 points on the line
y - y1 = m(x - x1)
Where m is the slope and (x1 , y1) is a point on the line.

8. Writing the equation given the slope and a point on the line
1. Substitute the slope in for m and the point in for x1 and y1 into y – y1 = m(x – x1)
2. Put the equation in the correct form (slope- intercept or standard form  given in directions)

9. Slope is 5 and through (4, -2)
y – y1 = m(x – x1)
Examples:
Write an equation with the given point and slope.
Write your answer in slope-intercept form.
Slope is 5 and through (4, -2)

10. Slope is ½ and through (-8, 1)

11. Slope is and through (-1, 5)

12. 4. Slope is and through (0, 7)

13. Writing the equation of a line given 2 points
Find the slope between the 2 points
m = 𝑦 2 − 𝑦 1 𝑥 2 − 𝑥 1
Use the slope from above and choose 1 of the given points to substitute into the point-slope equation: y – y1 = m(x – x1)

14. Write the equation of the line that goes through the 2 points
Write the equation of the line that goes through the 2 points. Write your answer in slope-intercept form.
y - y1 = m(x - x1)
1. (8 , -1) and (2 , 5)

15. 2. Through (4, -1) and (1, 5)

16. 3. Through (5, 0) and (-3, 2)

17. 4. Through (-3, -4) and (6, 11)

18. Homework
Worksheet 1.3