Notation for the Superimposition of two or more equations

Question

Is there a mathematical notation that describes the superimposition of two or three equations?

For example, y=x superimposed on y-x^2, could you write that as y=x, x^2?

Thank you.

Answer 1

What do you mean by superimposed?

You can graph the 2 equations separately and superimpose the graphs.

But in order to answer your question, I need to know what your question means.