Use the labeled points at $x=0$ and $x=1$ to see what factor the output is multiplied by when $x$ increases by 1.

An exponential function can be written as $f(x)=a\cdot b^x$. Use $f(0)$ to get $a$, then use another point to find $b$.

In Desmos, plot the points you can read from the graph, such as $(0,3)$, $(1,9)$, and $(2,27)$.

Enter each option as a separate equation (for example, $y=3^{x+1}$, $y=3^x+3$, and so on).

Check which equation’s graph passes through all of the plotted points. Choose the option whose curve matches those points and the overall increasing shape.

From the graph, the curve passes through $(0,3)$, so $f(0)=3$.

For an exponential function, this means $f(x)$ can be written as $f(x)=3\cdot b^x$ for some constant $b$.

The graph also shows the point $(1,9)$, so $f(1)=9$.

Substitute $x=1$ into $f(x)=3\cdot b^x$:

So $b=3$.

With $b=3$, the function is

So the correct choice is $f(x)=3^{x+1}$.