Function notation is an important idea when we learn about linear functions.

It helps us show how different variables are connected in a simple way.

Instead of writing $y = 2x + 3$, we can write it as $f(x) = 2x + 3$.

This way of writing has some key benefits:

1. Clarity: It's easy to see that $f$ is a function based on $x$.

2. Evaluation: We can quickly find out what the function equals. For example, if we plug in $2$, we get $f(2) = 2(2) + 3 = 7$.

3. Graphing: You can picture $f(x)$ as a line on a graph. Each $x$ value gives us one specific $f(x)$ value.

When we understand function notation well, we build a strong base to learn about more complicated functions later!