For you to represent a multiple system on a graph, first you need to know that it consists of different variables which are dependent and independent variables.
The independent variables are constant and the dependent variables changes with respect to the data presented.
The X and Y axis of a graph houses this variables depending on how the data is analysed and it is plotted one by one until all the data is being represented in the graph. For multiple systems, you will get more then one line either linear, sinusoidal...e.t.c but with reference to a common independent variable.
Multiple representations of a system be graphed an their key features can be compared when the different variables a represented in same graph at same time making reference to the graph.
Use of multiple representations supports and requires tasks that involve decision-making and other problem-solving skills.[The choice of which representation to use, the task of making representations given other representations, and the understanding of how changes in one representation affect others are examples of such mathematically sophisticated activities. Estimation, another complex task, can strongly benefit from multiple representations
Curricula that support starting from conceptual understanding, then developing procedural fluency, for example, AIMS Foundation Activities, frequently use multiple representations.
Supporting student use of multiple representations may lead to more open-ended problems, or at least accepting multiple methods of solutions and forms of answers. Project-based learning units, such as WebQuests, typically call for several representations.
The point at which the graphs intersect each other is the solution of the problem.