Which of the following options results in a graph that shows exponential growth?

f(x) = 0.4(3)x
f(x) = 3(0.5)x
f(x) = 0.8(0.9)x
f(x) = 0.9(5)−x

1 answer

to write
5 to the third power you type
5^3
so maybe I am guessing the first one might be
f(x) = .4* 3^x ???
that would be like
.4*3
.4*9
.4*27 etc, growing exponentially
----------------------
however
3 * .5^x
would be like
3 * .5
3 * .25
3 * .125
sinking like a rock
same for .9^x
now
.9 * 5^-x
would be like
.9 * 1/5
.9 * 1/25
.9 * 1/125
sinking even faster