What is the average rate of change for this exponential function for the interval from x=2 to x=4?

You would need the function equation.

Use slope for (y2-y2/x2-x1) to find the average slope.

Plug 4 into the function. The answer is y2 (4 is x2)

Plug 2 into the function. The answer is y1 (2 is x1)

(Y2-y1) / (4-2)

(y2-y1) / 2

That is how you would get the average rate of change.