Question

what does this mean?

Which of the following relations is a function?

a. {(4, 5), (6, 7), (8, 9), (8, 11)}
b. {(2, 0), (2, 1), (2, 2), (2, 3)}
c. {(3, 5), (4, 7), (5, 9), (5, 11)}
d. {(0, 2), (1, 2), (2, 2), (3, 2)}

Answer 1

A function is a set of ordered pairs in which each x-element has only ONE y-element associated with it.

Answer 2

So basically, for it to be a function, you cant have 2,6 and 2,7 because that means that the x element (2) has two different y elements.

Answer 3

For a function note these point

every element of set domain must be used .
every element of set domain must have only one image

now guess what is the correct answer

Answer 4

@wolftears what is the correct answer

Answer 5

its not c

Answer 6

or d im thinking

Answer 7

a vertical line test is used to determine if we have a function or not, but then we have to plot these points manually and that might not be the best way to handle this. We usually focus on the x values. So any x value repeating itself is not a function.

Answer 8

pick the one where there is no repeat in the first number in each ordered pair
for example 2 is not right because \[b. {(\color{red}2, 0), (\color{red}2, 1), (2, 2), (2, 3)} \] the 2 repeats

Answer 9

ok now that B isn't the answer . Let's look at the x-values for a c and d

a. 4 6 8 8
c. 3 4 5 5
d. 0 1 2 3

can you see which multiple choice is repeating?

Answer 10

c and a
bc c is 55 and a is 88

Answer 11

yes and since d has no repeating x values...that's a function