How do i decide whether a relation is a function or not ?

If the table of the function contains exactly two potential turning points, one with an input value of –1, which statement best describes all possible values of m? m ≥ –12 –12 < m < 4 m ≤ 4 m ≥ 4 or m ≤ –12

Percent increase and decrease. original number: 45 new number: 18

(60 points) explain this in detail