Select all relations that represent function

The last three are all functions.

The first one is not because by defenition of function, an x value cannot have two y values.

The second one is because a function f(x) is the same thing as y

The third one is because x value does not repeat, and that is all that matters.

The fourth one is a function too since x values do not have two y values

see explanation

step-by-step explanation:

since the sequence is geometric there is a common ratio r between consecutive terms, that is

r = 4 ÷ - 2 = - 2

r = - 8 ÷ 4 = - 2

r = 16 ÷ 8 = - 2

the next term - 13 must be incorrect as it should be - 32 for the sequence to be geometric.

the first 4 terms are therefore geometric with common ratio r = - 2