The expected value is $8,000.
The last part answers the first part for you, just look at the y-values.
In other words:
<em>A'</em><em> </em>(-8, 2)
<em>B'</em> (-4, 3)
<em>C'</em> (-2, 8)
<em>D'</em> (-10, 6)
Explanation:
When you reflect any point over the x-axis, the y-value of the ordered pair is going to change.
This makes sense especially considering that the x-axis is horizontal, so the only way you could cross is to move up or down. If you were to move left or right, you'd only be able to cross the y-axis, since it's vertical.
Now for the last part, as I mentioned above, if you are reflecting across the y-axis, the x-values of the ordered pair is going to change.
<em>A'</em><em>'</em> (8, 2)
<em>B'</em><em>'</em> (4, 3)
<em>C'</em><em>'</em> (2, 8)
<em>D'</em><em>'</em> (10, 6)
Take note that the only thing that changes for the respective value is its sign, while the number itself stays the same.
We determine line m as follows:
*First, by theorem we have the following:

Here m1 & m2 are the slopes of two perpendicular lines. For all lines that are perpendicular that is true, so we calculate the slope of line m using the slope of the function given [Which has a slope of 7/4]:

So, the slope of line m is -4/7. Now, using this slope and the point (-1, 4) we replace in the following expression:

Here x1, y1 & m1 are the x-component of the point, the y-component of the point, and the slope of the line respectively, so we replace and solve for y:


And that last function of y is the line m.