Step by step
The question
Question: find f(2) on this graph of f.
f(2) = ?
1 Look at the graph
The graph shows f.
x goes across.
The height of the graph is f(x): we read it on the y axis.
x: across
f(x): the height, up
2 Read f(2)
The number in the brackets is the x.
Here x is 2.
f(2): x = 2 → f(x) = ?
Careful!
f of 2 does not mean a height of 2.
The 2 in the brackets is an x.
So we start at 2 on the x axis.
Careful: f(2): start at x = 2, not at a height of 2
So f(2) = 3.
f(2) = 3
3 Check
Let's check.
The answer gives a point.
(2, 3) means right 2, then up 3.
It lands on the graph.
So the answer is right!
(2, 3): right 2, up 3 → on the graph
Let's look back.
First: look at the graph.
Then: read f(2).
Last: check.
Answer
f(2) = 3