What is the constant rate of change

The (constant) rate of change with respect to the variable x of a linear function y = f(x) is the slope of its graph. If x and f have units in Definition 2, then the units of the rate of change are those of f divided by those of x.

Explanation:

If the rate of change is constant, a graph of the measured quantity vs. time will be a straight line, and you can find the rate of change by calculating the slope of the line. If the rate of change is not constant, a graph of the measured quantity vs. time will be curved instead of straight.

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