To reflect a point in the x-axis, use the same x-coordinate and take the opposite of the y-coordinate. To reflect a point in the y-axis, use the same y-coordinate and take the opposite of the x-coordinate.
(9,0)
Practice makes perfect
We want to reflect a point in the x-axis and then in the y-axis of a coordinate plane. We need to follow two rules to do this.
To reflect a point in the x-axis, we use the same x-coordinate and take the opposite of the y-coordinate.
To reflect a point in the y-axis, we use the same y-coordinate and take the opposite of the x-coordinate.
Point
Reflection in the x-axis
Reflection in the y-axis
( x, y)
( x, - y)
( - x, - y)
( -9, 0)
( -9, 0)
( 9, 0)
As we can see, the reflection of the point is at (9,0). Note that the reflection in the x-axis does not change the coordinates of the point. This is supported by the fact that its y-coordinate is 0, and opposite number to 0 is 0. Let’s plot our point and its reflections on the coordinate plane.
We can see that the point is located at (9,0) after both reflections.
Extra
More About Coordinate Planes
A coordinate plane is formed by the intersection of a horizontal number line and a vertical number line. The number lines intersect at the origin and separate the coordinate plane into four regions called quadrants. An ordered pair is used to locate a point in a coordinate plane. The first coordinate represents the x-axis and the second coordinate the y-axis.
