Are these 3 separate questions?
Step-by-step explanation:
Any number divided by zero, its value can't be determined. Hence it is called as indeterminate form. So is with zero divided by zero.

Answer:118%
Step-by-step explanation: You would subtract 1200 by 550 and put that answer (118) over 1000 and then that would be your percent 118%.
Answer:
Addition property of equality.
Hope this helps :)