1. The Cartesian Coordinate System and Linear Equations in Two Variables
Section 7.1
The Cartesian Coordinate System and Linear Equations in Two Variables

2. The Vocab…
The cartesian system is comprised of 2 number line, the x axis and the y axis.
The axes intersect at the origin.
The plane is divided into 4 sections, called Quadrants. These are labeled I, II, III, and IV.
Each point on the cartesian system is given an ordered pair “address” in the form (X, Y)

3. EX: Plot each point and state the Quadrant
B (1, -3)
C (0, 1)

4. EX: List the Ordered Pair and Quadrant for each Point:
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      

5. To determine if a point is a solution:
Substitute the values for x and y into the equation. If the left and right side of the equation are the same, the point is a solution!
EX: Which ordered pairs are solutions to the equation -3x + y = -7?
(2, -1); (0, 4); (5, 8)

6. Collinear Points
Collinear points are points that lie on the same STRAIGHT line.
EX: Plot the points. Are they collinear?
1. (2, 1); (0, -1); (-3, -1)
2. (1, 1); (0, -1); (2, 3)