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