Answer
$f$ is exponential, $g$ is not.
$f(x)=5(0.5^{x})$
Work Step by Step
Exponential models have form: $y=Ab^{x}$
When $x$ increases by one unit, the value of$ f$ is multiplied by $b.$
$A=f(0)$
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When $x$ increases by one unit,
the value of$ f$ is halved (multiplied by $b=0.5$), so $f$ is exponential.
since $A=f(0)=5,$ the exponential model is $f(x)=5(0.5^{x})$
Exponential functions can never have a value of zero,
so $g$ is not exponential, because $g(2)=0$.
