A reflection is a common type of transformation. To reflect a point across the<em> x-axis,</em> we consider this axis to be a mirror. On the other hand, if you want to reflect a point across the <em>y-axis, </em>you need to consider this axis to be a mirror. A coordinate grid is the <em>rectangular coordinate system</em>. Just as we can represent real numbers by points on a real number line, we can represent ordered pairs of real numbers by points in a plane called the <em>rectangular coordinate system</em>, or <em>the Cartesian plane</em>. So:
<h2>1. Point B.</h2>
If you reflect a point across the x-axis, the x-coordinate remains the same, but the y-coordinate changes into its opposite. So, if we have a point , the reflection of this point across the x-axis is the point . Finally, our point A changes into:
Point B:
<h2>2. Point C.</h2>
If you reflect a point across the y-axis, the y-coordinate remains the same, but the x-coordinate changes into its opposite. So, if we have a point , the reflection of this point across the y-axis is the point . Finally, our point A changes into:
Point C:
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<h3><em>Below are illustrated all these points in the coordinate grid.</em></h3>