If we say that this linear function is [tex]f(x)[/tex], then the input of the function would be defined by [tex]x[/tex], which is 2 in this case.
This basically means we are finding [tex]f(x)[/tex] when [tex]x[/tex] is 2, or [tex]f(2)[/tex], or in layman's terms, what the [tex]y[/tex] value is when [tex]x[/tex] is 2.
If we find 2 on the [tex]x[/tex]-axis, and see where the line is on the [tex]y[/tex]-axis, we see that when the input of the function is 2, the output is -6.
Hope this helps!
