Answer:
F(x)=3^5(1/4)^x
Step-by-step explanation:
By the exponential decay definition: y = ab×
b determines the rate at which the graph grows: if b > 1, the function will increase. if 0 < b < 1, the function will decrease.
There is only (1/4)ˣ : where 0<1/4<1 fit the definition, so F(x)=3^5(1/4)^x is the choice
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But.. look at the table attached, the f(x)=3(1.7)^-2x and F(x)=3^5(2)^-x also showed pattern of decay. It can verified from their graphs. (Try plot it with your calculator)
