Which is an exponential decay function?

Karthik · May 8, 2019, 5:44am

a. f(x) = 3over4(7over4)^x
b. f(x) =2over3(4over5)^–x
c. f(x) = 3over2(8over7)^–x
d. f(x) = 1over3(9over2)^x