The server will give you the graph of a function *f* (x), whose expression
will be hidden. You will then be presented a certain number of other graphs,
corresponding to modifications of *f* (x) such as *f* (-x),
2*f* (x), *f* (x-1), etc (see the menu below). And you should locate the one
which corresponds to one which will be precised in a question.
To give the reply, you can simply click on the graph which you believe to be
the good one.