The x-axis is a horizontal line on a coordinate plane. It extends to the right in the positive direction and to the left in the negative direction. It is perpendicular to the y-axis, which is the vertical line on the coordinate plane. To help visualize this, imagine a simple graph with a horizontal line going through the center. The line that goes from left to right is the x-axis. Moving to the right along the x-axis means increasing the x-coordinate values, while moving to the left means decreasing the x-coordinate values. In summary, the x-axis goes horizontally from left to right, representing the positive and negative values of the x-coordinate on a graph.