X1 and x2 were measured but x is unknown what should x be to minimize the abs(x-x1) and abs(x-x2)?

Question

abs stands for absolute value

Answer 1

What do you want to minimize now? ... If x = x1, then |x-x1| is minimized (since it's zero).  Likewise with x = x2 in the other expression.

If you want to minimize the sum |x-x1| + |x-x2|, then you should choose any x between the values x1 and x2, inclusive.