Section 2.1
The Cartesian Coordinate System breaks the plane into four quadrants by bisecting the space with a vertical y-axis and a horizontal x-axis. The point where the axes meet is called the origin. Each point on the coordinate plane is distinguished by an ordered pair (x, y).
Watch this video to see how the Cartesian Coordinate system is drawn and how points are graphed in the plane.
Now that we can graph points, we can use the Cartesian Coordinate System to graph equations in two variables by plotting points.
Watch this video to see how we graph two lines in the plane by plotting points on the line.
The intercepts of a graph are points at which the graph crosses the axes. The x-intercept is where the graph crosses the x-axis, and the y-intercept is where the graph crosses the y-axis.
When the graph crosses the x-axis, the y-coordinate is 0. Thus, to find the x-intercept, set y=0 and solve for x. When the graph crosses the y-axis, the x-coordinate is 0. Thus to find the y-intercept, set x=0 and solve for y. Remember, intercepts are points, so your answer should always be an ordered pair!
Watch this video on finding intercepts.