Answer: Fourth option.
Step-by-step explanation:
By definition, a relationship is a function if and only if each input value (or each x-value) has only one output value (or y-value).
Given the first table:

You can notice that the input values 2 and 3 do not have only one output value. Therefore, this table does not represent a function.
The second table is:

You can notice that the input values 4 and -4 do not have only one output value. Therefore, this table does not represent a function.
The third table is:

You can notice that the input values 6 and 7 do not have only one output value. Therefore, this table does not represent a function.
The fourth table is:

You can notice that each input value has only one output value. Therefore, this table represents a function.
Answer:
Yes you are correct.
Step-by-step explanation:
The best way to check theese types of questions is go back in plug in X with your answer so 88+97+80+90(which is x)=360 then divide by 4 and get 90! So yes you are correct good job!
Answer:
Step-by-step explanation:
2+2=4 that give you your answer
Answer:
The average would be 15; the numbers would be 13, 15, 17. Can be done, also, by Algebra: x-2, x & x+2 are the numbers; set their sum to 45 and solve
Step-by-step explanation:
Hope this helps