The most general linear map of $\mathbb{R}^n$ to $\mathbb{R}$ Find the most general linear map of $\mathbb{R}^n$ to $\mathbb{R}$.

Obviously, dot product is one. However, I'm not sure how do I show that it's the most general of them? Or maybe, something else is even more general? Hint appreciated!
As with any two finite dimensional vector spaces, $V$, $W$, you can fix a basis for $V$ and a basis for $W$ and then the linear transformations from $V$ to $W$ become rectangular matrices which you perform matrix multiplication with.

So, one could say that a general linear transformation from $\Bbb R^n$ to $R$ can be identified with a matrix $[a_1,\dots a_n]$ where $T(x_1,\dots x_n):=[a_1,\dots a_n][x_1,\dots, x_n]^\top \in \Bbb R$.

You can see that this means all linear maps arise as the dot product of some fixed vector with other vectors.
Hint: What is the dot product?