<p>I got it right, but I was confused about the reasoning.</p>
<p>In the xy-coordinate plane, line m is the reflection of line l about the x-axis. If the slope of line m is -4/5, what is the slope of line l?
4/5</p>
<p>Thanks!</p>
<p>A reflection about the x-axis means that for every (x,y), the reflected point will be (-x,y). This means that the slope of the second line will be the negative value of the slope of the first line. </p>
<p>Let’s say we have two points (3,4) and (5,8) on line A. The slope of this line is:</p>
<p>(8-4) / (5-3) = 2</p>
<p>If we reflect it over the x-axis, the points will be (-3,4) and (-5,8). The new slope is:</p>
<p>(8-4) / (-5–3) = 4/-2 = -2 which is just the slope of line A times -1.</p>