What does the line x equals -y look like on a graph?

The line ( x = -y ) can be rewritten as ( y = -x ), which represents a straight line with a slope of -1. This line passes through the origin (0,0) and extends equally in the first and third quadrants as well as the second and fourth quadrants, forming a diagonal line that makes a 45-degree angle with both the x-axis and y-axis. The line falls from the upper left to the lower right of the graph.