Function/Relation?

Question

Problem 1:
Which one is a RELATION but not a function

Choices:
1) {(-10,1),(1,8),(-4,-2)}
2) {-4,1),(1,1),(-2,-2)}
3) {(-5,1),(1,-7),(21,-2)}
4) None


Problem 2:
Which of the following is a function

Choices:
1) {(-4,1),(1,8),(-4,-2)}
2) {(-4,1),(1,-8),(-2,-2)}
3) {(-4,1),(1,-8),(1,-2)}
4) None

Answer 1

Problem 1:
Which one is a RELATION but not a function

Choices:
1) {(-10,1),(1,8),(-4,-2)}
function
2) {-4,1),(1,1),(-2,-2)}
function
3) {(-5,1),(1,-7),(21,-2)}
function
4) None


Problem 2:
Which of the following is a function

Choices:
1) {(-4,1),(1,8),(-4,-2)}
relation
2) {(-4,1),(1,-8),(-2,-2)}
function
3) {(-4,1),(1,-8),(1,-2)}
relation
4) None
`

Answer 2

Prob 1: none of the above. Each relation has three distinct x values, which means they are each functions.

Prob 2: the second one. The other two have a repeated x value, which is not allowed for functions.

Answer 3

1) none
because the first three choices are function
2) choice 2
because there is x's that are the same