1. Warm Up – 1/27 - Monday Sketch a graph of the piecewise function:
𝑓 𝑥 = 𝑥− 𝑖𝑓 𝑥>1 −2𝑥−1 𝑖𝑓 𝑥≤1
On your graph, have your axes extend from -5 to 5.

2. Today’s Goal
Write the equations of each piece of a linear piecewise function and identify the domains.

3. Writing the Equations of a line
Step-By-Step:
Find the coordinates of 2 points.
Use the slope formula to find the slope.
𝑚= 𝑦 2 − 𝑦 1 𝑥 2 − 𝑥 1
3. Plug slope and one of the points into
𝑦=𝑚𝑥+𝑏.
4. Solve for b.
5. Re-write 𝑦=𝑚𝑥+𝑏 plugging in 𝑚 and 𝑏

4. Example #1

5. Solution (0, 4) and (2, 1) 𝑚= 4−1 0−2 =− 3 2 𝑦=− 3 2 𝑥+𝑏 4=− 3 2 0 +𝑏
4=− 𝑏
4=𝑏
4. 𝑦=− 3 2 𝑥+4
(0, 4)
(2, 1)

6. Example #2

7. Linear and Horizontal Lines

8. Example #3

9. Writing the Equation of a Piece-wise function
The steps remain the same.
You must perform the steps
For each piece!