In this context, 2x represents a linear function where y (or f(x)) is equal to two times x. It describes how y varies as x increases or decreases.
A function that can be represented by a straight line on a graph.
The measure of how steep or flat a line is. In the case of 2x, the slope is 2.
Constant Rate of Change: When the change in y divided by the change in x remains constant.