Step by step
The question
Question: reflect the point P(−4, 1) in the x-axis.
1 Draw the shape
Put the point on the grid.
2 Draw the mirror line
The mirror line is the x-axis.
Reflecting flips the shape over the line, like a mirror.
Each point lands just as far away, on the other side.
3 Reflect each point
From P, count straight to the mirror line: 1.
Then count 1 more on the other side.
We call the new point P prime.
The little mark means: the new P.
P is 1 above the x-axis.
Its image is 1 below it.
Its x stays −4.
So P' is (−4, −1).
Careful!
The x-axis is flat.
The flip goes up or down, so y changes.
x stays.
4 The new point
So the image is P'(−4, −1).
5 Check
Let's check with the rule for the x-axis: x stays the same, y changes sign.
It gives the same points.
Right!
Let's look back.
First: draw the shape.
Then: draw the mirror line.
Then: reflect each point.
Then: the new point.
Last: check.