Which of the following does not represent a function?

x 2 3 5 8
y 7 11 15 20

x −4 −2 0 5
y 3 −1 −1 10

x −5 −3 −2 0
y −32 −2 −8 −3

x −3 −3 6 2
y 0 1 5 4

Question

Which of the following does not represent a function?

x	2	3	5	8
y	7	11	15	20

x	−4	−2	0	5
y	3	−1	−1	10

x	−5	−3	−2	0
y	−32	−2	−8	−3

x	−3	−3	6	2
y	0	1	5	4

jim_thompson5910 · Answer

Which one of these has an x value mapping to more than one y values?

anonymous · Answer

i dont get it im really bad in math

jim_thompson5910 · Answer

In the first choice, notice how x = 2 maps to x = 7

jim_thompson5910 · Answer

Do you see what I'm referring to?

anonymous · Answer

yea

jim_thompson5910 · Answer

In that first choice, does x = 2 map to any other y value?

anonymous · Answer

i think no

jim_thompson5910 · Answer

Good, what about x = 3?

jim_thompson5910 · Answer

What does that map to?

anonymous · Answer

like what do u mean by map?

jim_thompson5910 · Answer

basically, you have some function (we don't know what it is), but what this function does is take inputted x values and "maps" them or assigns them to a corresponding y value

jim_thompson5910 · Answer

ex: the function y = 2x  takes the input of x = 5 and maps it to y = 10 since plugging in x = 5 gives you y = 10

jim_thompson5910 · Answer

So in the first choice, when x = 3, what is y?

anonymous · Answer

would it be 15?

jim_thompson5910 · Answer

No, look at the number directly under 3

anonymous · Answer

11

jim_thompson5910 · Answer

so that means that when you plug x = 3 into this unknown function, you'll get y = 11 out

jim_thompson5910 · Answer

Is there any other place in this first table where you plug in x = 3 and get some other value?

anonymous · Answer

yes

jim_thompson5910 · Answer

Where

jim_thompson5910 · Answer

Look at the first table only

anonymous · Answer

would it be 15

jim_thompson5910 · Answer

No, that's the corresponding output for the input of x = 5

anonymous · Answer

ohhh

jim_thompson5910 · Answer

What goes in is on top (the x row) and what comes out is directly beneath it (the y row)

jim_thompson5910 · Answer

Ex: in goes x = 3, out comes y = 11

anonymous · Answer

so it would be no

jim_thompson5910 · Answer

you got it, there's only one input of 3 in that first table

jim_thompson5910 · Answer

So what you're looking for is this:

If you plug in a certain value, and you get more than one number out, then it will tell you that this table is NOT a function

jim_thompson5910 · Answer

Ex: if I plug in x = 3, and I get y = 11 AND y = 15 at the same time, then it wouldn't be a function

anonymous · Answer

so im guessing the answer would be the 1st one?

jim_thompson5910 · Answer

why do you say that?

anonymous · Answer

i dont know

jim_thompson5910 · Answer

Is there any number x we plug in that results in more than one y value output?