HELP ME WITH THIS

Question

In the coordinate plane, the points
X−10, 8
,
Y−2, 3
, and
Z11, 6
are reflected over the
y
-axis to the points
X '
,
Y '
, and
Z '
, respectively. What are the coordinates of
X '
,
Y '
, and
Z '
?

Answer 1

Hi Sophie--

 

Do you have the graph drawn out to look at? It's much easier to think about when you can see it.

 

Now, imagine if the original points were dots of wet paint. If you fold your paper along the y (vertical) axis, and press down, you'll get paint dots in the right places.

 

So -10,8 folds over the y axis and becomes 10, 8.

 

Do the same with the next 2 points. (Careful with Z, it's going to move in the opposite direction.)

 

Does this help? Let me know if you need more hints, but I bet you can get it from here. :-)

 

Matt in NY

Answer 2

When a point is reflected across the y-axis, the

x-coordinate changes sign while the y-coordinate remains the same.  

 

So, (-10, 8)→(10, 8)

      (-2, 3)→(2, 3)

      (11, 6)→(-11, 6)