Step by step
The question
Question: reflect the point P(2, 3) in the line x = 4.
1 Draw the shape
Put the point on the grid.
2 Draw the mirror line
The mirror line is the line x = 4.
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: 2.
Then count 2 more on the other side.
We call the new point P prime.
The little mark means: the new P.
P is 2 left of the line.
Its image is 2 right of it.
Its y stays 3.
So P' is (6, 3).
Careful!
Count to the mirror line x = 4, not to the y-axis.
4 The new point
So the image is P'(6, 3).
5 Check
Let's check: the mirror line is halfway between a point and its image.
Halfway between 2 and 6: add them, then divide by 2.
That is 4: the line x = 4.
Right!
Let's look back.
First: draw the shape.
Then: draw the mirror line.
Then: reflect each point.
Then: the new point.
Last: check.