Step by step
The question
Question: find f(4) in this table of f.
f(4) = ?
1 Look at the table
The table shows f.
Each x on top has its f(x) right under it.
For example, f of 0 is 5.
x: top row
f(x): right under its x
2 Read f(4)
The number in the brackets is the x.
Here x is 4.
f(4): x = 4 → f(x) = ?
Careful!
f of 4 does not mean f(x) is 4.
The 4 in the brackets is an x.
So we start at 4 on the x row.
Careful: f(4): start at x = 4, not at f(x) = 4
Find 4 in the x row.
Right under it is −3.
So f(4) = −3.
f(4) = −3
3 Check
Let's check the other way.
The −3 in the bottom row sits under x = 4.
So the answer is right!
column: x = 4, f(x) = −3
Let's look back.
First: look at the table.
Then: read f(4).
Last: check.
Answer
f(4) = −3