You didn't describe the situation so I can't answer.
However: if the graph of the situation is a straight line then the situation is linear, and if the graph is not a straight line then it is nonlinear.
Answer:
Completing the experiment a few more times and combining the results to the trails already done.
(3x+4) units.
Working;
AM=AD+DM
=x+5+2x-1
=(3x+4) units
