On this graph, coordinate P lies 2 units to the left of the center. The side-to-side movement of a point on a coordinate plane is called movement on the x-axis, and since it is 2 units to the left of the center, it is called -2. All units to the left of the zero point (middle of the graph) is counted in negative numbers.
Coordinate P also lies 4 units down from the center. Movement up and down the graph is called movement on the y-axis, and since it is 4 units below the center, it is called -4. All units below 0 on the y-axis are counted in negative numbers.
To assemble our coordinates, we just have to remember the format for coordinates on a plane, which is (x, y). The value of the point's position on the x-axis always comes first, followed by its position on the y-axis. In this case, the finished coordinate would be (-2, -4).
Hope that helped! =)