Step by step
The question
Question: for which x is f(x) = 0 on this graph of f?
f(x) = 0 x = ?
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 Find where f(x) = 0
This time we know f(x): it is 0.
We look for the x.
f(x) = 0 → height 0 → x = ?
Careful!
Do not stop at the first x.
The graph can have the same height more than once.
Careful: look for every x: f(x) can be 0 more than once
So x = −2 or x = 2.
x = −2 or x = 2
3 Check
Let's check.
Each answer gives a point.
(−2, 0) means left 2, then stay at 0.
It lands on the graph.
(−2, 0): left 2, stay at 0 → on the graph
And (2, 0) means right 2, then stay at 0.
It is on the graph too.
So the answer is right!
(2, 0): right 2, stay at 0 → on the graph
Let's look back.
First: look at the graph.
Then: find where f(x) = 0.
Last: check.
Answer
x = −2 or x = 2