The domain number $b$ is a zero of $f$, if $f(b) = 0$.

The point corresponding to the zero $b$ is $(b, f(b)) = (b, 0)$, an intercept.

Here is the complete graph of the function $G(x)$.

The graph has one intercept, which means that $G$ has one zero, whcih appear to be $2.8$.

$$G(2.8) = 0$$

The graph is another intercept: $(0, 1.7)$. This tells us that $G(0)=1.7$. However, this is not really useful information in functional analysis.

If this function was a model for some timed event, then perhaps $t = 0$, would be important to the situation. But that is an interpretation that is important.

When analyzing a function, we are mostly interested in its zeros, which correspond to intercepts on the horizontal axis.