Step by step
The question
Question: reflect the point P(3, 2) in the y-axis.
1 Draw the shape
Put the point on the grid.
2 Draw the mirror line
The mirror line is the y-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: 3.
Then count 3 more on the other side.
We call the new point P prime.
The little mark means: the new P.
P is 3 right of the y-axis.
Its image is 3 left of it.
Its y stays 2.
So P' is (−3, 2).
Careful!
The y-axis goes up and down.
The flip goes left or right, so x changes.
y stays.
4 The new point
So the image is P'(−3, 2).
5 Check
Let's check with the rule for the y-axis: x changes sign, y stays the same.
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.