Why is there the restriction that x1 cannot equal x2 in the geometric definition of the slope?

Why is there the restriction that x1 cannot equal x2 in the geometric definition of the slope?
 
Do you need a similar assignment done for you from scratch? We have qualified writers to help you. We assure you an A+ quality paper that is free from plagiarism. Order now for an Amazing Discount!
Use Discount Code "Newclient" for a 15% Discount!

NB: We do not resell papers. Upon ordering, we do an original paper exclusively for you.