Help me 1. Circle each relation that is a function.
{(1, 3), (1, 5), (2, 7), (3, 9), (4, 11)}
{(0, 0), ( 21, 21), ( 22, 22), ( 23, 23)}
{(5, 5), (5, 4), (5, 3), (5, 2)}
{(2, 5), (3, 5), (4, 5), (5, 5)}

2 and 4

Step-by-step explanation:

A relation describe a function when for every x is associated one and only one y

1) is not a function because when x = 1 there are two y associated (3 and 5)

2)  yes, for the definition of function

3) is not a function because when x = 5 there are four y associated ( 5, 4, 3, 2)

4) yes, because for every x there is only one y associated (is not important if is the same)

step-by-step explanation:

b and c

(1, –1), (16, –4), (36, –6)

step-by-step explanation:

given that the function is

this can also be written as

we have to graph this function and check which list of points lie on the graph

see attachment for graph:

we find that the points lying are (1,-1) (16,-4) and (36,-6)

since square root is there we find that x can only be posiitve but y can be since square root both positive and negative.