Question

Which order pair could you remove from the relation {(-2,-1),(-1,1),(-1,0),(0,1),1,0)}

Answer 1

What's the point here?  Why would you remove one of the ordered pairs?

The only thing I see here that hints at an answer is that -1 is the first term of both (-1,1) and -1,0).  If we got rid of one of these, then the relationship could be a function; otherwise it is not a function.  Why?  Because in the case of a function, all first elements of the ordered pairs are unique (different from all the other first elements).