2. * Slope-Intercept form * Used to graph a line * Used to find equations of lines * Point-Slope form * Used to find equations of lines Writing Equations of Lines Given Point and slope y = mx + b slope point ( x 1, y 1 ) y - y 1 =m(x - x 1 ) We will find the equation of a line given a point and a slope! What is point-slope form?

4. Cornell Notes EXAMPLE 1 – Slope Int Form Write an equation in slope-intercept form of the line whose slope is m = -2 and passes through the point (6, -3).

5. Example 1 You Try!!! Find the equations of the lines:

6. Write an equation in standard form of the line whose slope is m = 2/3 and passes through the point (1, 4). Cornell Notes EXAMPLE 2 – Standard Form

7. Example 2 You Try!!! Find the equations of the lines:

8. Write an equation in slope intercept form of the line thru (2, 3) and (4, -5). Cornell Notes EXAMPLE 3 – Slope Int Form

9. Example 3 You Try!!! Find the equations of the lines in slope-intercept form: Thru (-5, 4) and (-1, 6)

10. The figure shows trapezoid ABCD with bases AB and CD. Write an equation in point-slope form for the line containing the side BC. ___ Cornell Notes EXAMPLE 4 – Point-Slope Form

11. Example 4 You Try!!! The figure shows trapezoid ABCD with bases AB and CD. Write an equation in point-slope form for the line containing the side AD. ___

12. A.y = 3.5x + 57.65 B.y = 3.5x + 68.15 C.y = 57.65x + 68.15 D.y = –3.5x – 10 The cost of a textbook that Mrs. Lambert uses in her class was $57.65 in 2005. She ordered more books in 2008 and the price increased to $68.15. Write a linear equation to estimate the cost of a textbook in any year since 2005. Let x represent years since 2005. Cornell Notes EXAMPLE 5 – Real Life

13. Write Cornell Notes Summary 4.2/4.3 in Homework Packet IN CLASS REVIEW TOMORROW * Homework due Tuesday, Sept 29 th