1. 3.1 Graphing in 2-D Coordinates (Day 1)
Today’s Date:
10/30/17
Ch 3 TEST on
Wed 11/15

2. Linear Equation: Ax + By = C
To Graph: Find the x- and y-intercepts (x , 0) (0 , y) let y = 0 let x = 0 Solve for x Solve for y

3. Slope Intercept Form: y = mx + b
To Graph: Graph y-int (0, b)
Use slope (m) to find another point

4. Ex 1) Graph 2x + 3y = 6 & Find x- and y-int
Let x=0: 2(0) +3y = 6
3y = 6
y = 2
(0, 2)
Let y=0: 2x +3(0) = 6
2x = 6
x = 3
(3, 0)
Y-int
X-int
Graph intercepts and connect the dots

5. Graph (0, 2) and (3, 0) and connect dotsy x
(0, 2)
(3, 0)

6. Ex 2) Graph & find x- and y-int
y = mx + b
Ex 2) Graph & find x- and y-int
 y-int
Find x-int: Let y = 0 y x
(0, 2)
(2, –3)

7. Two Special Cases x = -3 (no y) y = 2 (no x) Undefined Zero
I only see an “x”
It goes thru x-axis
x = (no y)
I only see
a “y”
It goes thru y-axis
y = (no x) y x y x
Undefined
Zero
Vertical line thru
(-3, 0)
Undefined Slope
Horizontal line thru
(0, 2)
Zero Slope

8. Slope Formula Given 2 points: (x1, y1) and (x2, y2)
The slope of the line through the points is

9. Ex 3) Find the slope of the line through (- 3, - 4) and (7, - 2)
x y1
x y2

10. Special Cases

11. Midpoint Formula

12. Ex 4) Find the midpoint of (4, 0) and (- 10, 3)
x y1
x y2

13. Homework
#301 Pg – 29 odd

14. 3.1 (Day 2) Graphing in 2-D Coordinates
Today’s Date:
10/31/17

15. Given Ax + By = C, find slope
Ex 1) Find the slope of 4x – 2y = 20 A = 4 B = –2

16. OR Rewrite in Slope-Intercept Form y = mx + b and find slope (m)
4x – 2y = 20
–2y = –4x + 20
y = 2x – 10
m = 2

17. Set each coordinate part = to each other
Ex 2) Midpoint = (–2, 7) & One Endpoint = (3, –5). Find other endpoint.
(x1 , y1)
Find
(x2 , y2)
Set each coordinate part = to each other

18. And solve for x and y:
Other endpoint: (–7, 19)

19. Ex 3) Suppose the 3 points lie on a straight line. Find missing coord.
(1, –1), (–2, 8), (x, –7) Find slope, use (1, -1) & (-2, 8): Use slope & these 2 points (-2, 8) & (x, -7):

20. Make a table and plug values into y and solve for x
Ex 4) Sketch the graph of
Plug in -2, -1, 0, 1, 2 into y
Make a table and plug values into y and solve for x y x x
│y│ – 1 y 1 –1
│–2│–1
│–1│ – 1
│0│ – 1
│1│ –1
│2│ – 1 –2 –1 1 2

21. Plug values into y & solve for x
Ex 5) Sketch graph of
Plug in -2, -1, 0, 1, 2 into y
Plug values into y & solve for x y x x
y2 + 1 y 5 2 1
(–2)2 + 1
(–1)2 + 1
(0)2 + 1
(1)2 + 1
(2)2 + 1 –2 –1 1 2

22. HINT for Homework: Parallelogram (HW #51 & 53)
To determine vertices of Parallelogram:
Draw Sketch
Opp. Sides are parallel → same slope (m)

23. Homework
#302 Pg odd