1. Writing Equations of Lines

2. Do Now: Answer each of the following questions based on the graph 1.What is the slope of the line? 2.What is the y-intercept? 3. What is the equation of the line?

3. How do we write equations of lines? 1.Determine the slope 2.Determine the y-intercept 3.Sub slope (m) and y-intercept (b) into y = mx + b

4. Practice: 1.What is the slope of the line? 2.What is the y-intercept? 3. What is the equation of the line?

5. Practice: 1.What is the slope of the line? 2.What is the y-intercept? 3. What is the equation of the line?

6. How do we write equations of lines without the graph? 1. Example: Write an equation of the line whose slope is 3 and passes through the point (1,4). 1.What is slope (m)? 2.To find y-intercept: a. Sub m, x and y into y=mx +b b. Solve for b 3. Sub m and b into y=mx +b

7. Practice 2. Example: Write an equation of the line whose slope is - 2 and passes through the point (2,- 3). 1.What is slope (m)? 2.To find y-intercept: a. Sub m, x and y into y=mx +b b. Solve for b 3. Sub m and b into y=mx +b

8. How do we write equations of lines without the graph? 3. Example: Write an equation of the line that passes through the points (2,6) and (-2,10). 1.Find slope (m) using slope formula 2.To find y-intercept, pick one of the points given: a. Sub m, x and y into y=mx +b b. Solve for b 3. Sub m and b into y=mx +b

9. Practice: 4. Example: Write an equation of the line that passes through the points (-1,-2) and (2,10). 1.Find slope (m) using slope formula 2.To find y-intercept, pick one of the points given: a. Sub m, x and y into y=mx +b b. Solve for b 3. Sub m and b into y=mx +b

10. How do we write equations of lines without the graph? 5. Write the equation of a line whose slope is - 3 and y-intercept is 1. 1.Find slope (m) 2.Find y-intercept (b) 3.Substitute into y=mx+b

11. Practice 6. Write the equation of a line whose slope is 1/2 and y-intercept is -3. 1.Find slope (m) 2.Find y-intercept (b) 3.Substitute into y=mx+b

12. Practice 7. What is the equation of the line that is parallel to y - 2x = 4 and whose y-intercept is –1? 1.Find slope (m) 2.Find y-intercept (b) 3.Substitute into y=mx+b

13. Practice 8. What is the equation of the line that is parallel to y + 3x = 2 and whose y-intercept is 4? 1.Find slope (m) 2.Find y-intercept (b) 3.Substitute into y=mx+b

14. Practice 9. Write an equation of the line that is perpendicular to y = 2x + 4 and whose y-intercept is 2? 1.Find slope (m) 2.Find y-intercept (b) 3.Substitute into y=mx+b

15. Practice 10.Write an equation of the line that is perpendicular to y = ½ x - 2 and whose y-intercept is 1? 1.Find slope (m) 2.Find y-intercept (b) 3.Substitute into y=mx+b