1. Point-Slope Form of a Line 2.21

2. Domino Effect #4  http://www.mathalicious.com/lessons/domino-effect/teach http://www.mathalicious.com/lessons/domino-effect/teach

3. Finding the Linear Equation  The information we had about the pizzas did not tell us the price per topping for each pizza size or the base price for a pizza.  We were still able to find the equation of the line.  How?

4. From Pizza to Point-Slope Form of a Line (16.95 – 13.97) = 1.49(4 – 2) (y 2 – y 1 ) = m(x 2 – x 1 ) (y – y 1 ) = m(x – x 1 )

5. Point-Slope Form of a Line  Point-slope form  A linear equation written using the slope and one point from the line  (y – y 1 ) = m(x – x 1 )

6. Steps  Determine the slope of the line  Label the x and y values of one point  Substitute these values in for m, x 1, and y 1

7. Example Write the equation for the line that has a slope of 5 and passes through the point (-1, 8).

8. Example Write the equation for the line that passes through the points (-3, 0) and (1, -2).

9. Practice  Write the linear equation with the following set of characteristics. 1) Slope of -4; passes through (8, 5) 2) Slope of ½; passes through (6, -2) 3) Passes through (1, 4) and (7, 5) 4) Passes through (-1, 5) and (1, -3) 5) Passes through (-3, 0) and (-2, -5) 6) Passes through (-4, 3) and (2, 3)