The argument is valid by the law of detachment.
Another way to solve this is to use the Midpoint Formula. The midpoint of a segment joining points

and

is

So the midpoint of your segment is

Perhaps it helps to see that the x-coordinate of the midpoint is just the average of the x-coordinates of the points. Ditto for the y-coordinate of the midpoint; just average the y's.
The answer is -80, i have done all the math and -80 is the answer
Answer:
where is the figure?
Step-by-step explanation: