Question

Which ordered pairs lie on the graph of the exponential function f(x)=4(5)^2x

Answer 1

A. (-1, 4/25)

D. (2, 2500

Are the answers

Answer 2

There are four inputs:  {-1, 0, 1 and 2}.  Let x=-1 and find y.  Let x = 0 and find y.  And so on.  You will find that only the input -1 produces the y-value predicted by the function f(x) = 4(5)^(2x). 

Note that if you use a calculator to evaluate f(x), be certain to enclose "2x" inside parentheses:  f(x) = 4(5)^(2x)