Question

Determine whether the following relations are functions. Give the appropriate reason for your answer. *pictures included
a) {1,3), (2,3), (3,2), (1,4), (4,1)}
b) picture
c)picture
d)picture
e)picture

Answer 1

if you want to know that a relation is function look at the x of every ordered pair.if you saw that one of x is repeated and their y isn't same that relation isn't a function for example : {(1,2),(1,3)} is not a function.

Answer 2

for b
do two arrows come out of any number?

Answer 3

and for d and e we use a test :vertical line test
If a vertical line can be drawn that crosses two points on the graph of the relation, then the relation is not a function.

Answer 4

@amirreza1870 i see...but what if your x values aren't the same but one of y-values is repeated twice? Is that a function?