Question

calculate rate of change of function f(x) = (0.4)^x ;
x changes from x to x + 2.

kindly help in this
x = 0 and x = -2
rest i know how to solve
dont know the value of x

Answer 1

Huh? They give you the value of x. I read this as meaning when x=0
you want the average rate of change of f(x) between x=0 and x=2
f(x) = 0.4^x so
f(0) = 0.4^0 = 1
f(2) = 0.4^2 = 0.16
so the average rate of change is (0.16-1)/(2-0) = -0.42
That is the slope of the line from (0,1) to (2,0.16)

If I have it wrong, then please explain it further.