Question 1051013
You build a model based on the information you're given. 
So if your x value lies between -1 and 5, it should be pretty close to the real value. 
However for values less that -1 and greater than 5, you really have no information about how the function behaves. 
The value of x=100 is really far away from the region where your function is linearized.
I would have no confidence in a solution that far away.