For this problem we recall the definition of an exponential function:
[tex]\begin{gathered} f(x)\text{ is an exponential function if } \\ f(x)=a\cdot b^{kx} \\ \text{Where a}\ne0,\text{ k}\ne0\text{ and b}\ne1 \end{gathered}[/tex]Answer: F(x)= - 3 (2)^x