exponential formula:
![y=a\cdot b^x](https://img.qammunity.org/2023/formulas/mathematics/high-school/6has3k4sb3pm3ew4419r8bw5p19fprxq7e.png)
where a and b are two constants.
Replacing with x = 0, and y = 1, we get:
![\begin{gathered} 1=a\cdot b^0 \\ 1=a \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/xrroof0dti10x2cx919uuh7wu553hbtv44.png)
Replacing with a = 1, x = 1, and y = 3, we get:
![\begin{gathered} 3=1\cdot b^1 \\ 3=b \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/nvkc9q7zkmm8sj5rh5tbughu1vnpnozbma.png)
Then, the equation is:
![y=1\cdot3^x](https://img.qammunity.org/2023/formulas/mathematics/college/bznftm82aa274woc3jklhv5igax1f53e3a.png)
This result can be checked with the other points of the table.
When x = 2,
![y=1\cdot3^2=9](https://img.qammunity.org/2023/formulas/mathematics/college/1gh07yzc182c9t3482d1e29wqrw6ux9s5s.png)
When x = 3,
![y=1\cdot3^3=27](https://img.qammunity.org/2023/formulas/mathematics/college/w8nlrkhlguy5qnuipfqc3jwefvatlqsey4.png)