1. 3.1 Graphing in 2-D Coordinates

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

3. 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

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

5. 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)

6. 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

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

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

9. Special Cases

10. Midpoint Formula

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

12. Homework
#301 Pg – 29 odd