Question

which relation is not a function?
1) y=2x+4
2) y=x^2-4x+3
3) x=3y-2
4) x= y^2+2x-3

Answer 1

Any ideas?

Answer 2

its neither 1 or 3

i m stuck between 2 and 4

Answer 3

lol

Answer 4

In math we start with definitions, right?

Answer 5

What is the definition of a function?

Answer 6

for every x there is only 1 y

Answer 7

Yes...

Answer 8

look at the form of the equations given

Answer 9

for your idea to work they should be written how?

Answer 10

think about it

Answer 11

1) y=2x+4
2) y=x^2-4x+3
3) x=3y-2
4) x= y^2+2x-3

Answer 12

You said "for every x there is only 1 y"

Answer 13

yea

Answer 14

so that means what?

Answer 15

should i inverse choice 3 and 4 or something

Answer 16

i believe 4) is not a function

Answer 17

good you are getting the idea,,,choice 3 is OK because you can easily write as y = ... right?

Answer 18

yes

Answer 19

@amrita000 come on you can do it on your own

Answer 20

try

Answer 21

4) is not a function

Answer 22

how s square root not a function?

Answer 23

x= y^2+2x-3, y^2=-x+3, y=sqrt(-x+3), if x is bigger than 3 then it is an imaginary function

Answer 24

This is not true @AmardeepSingh

Answer 25

its |y|=sqrt(3-x) and that's the difference (the absoute value)

Answer 26

The question should read which relation is not a function of x @amrita000

Answer 27

$$\Huge y=f(x)$$

Answer 28

alright thanks .. i got it... its choice 4

Answer 29

Good work :-)

Answer 30

Thanks everybodyy!!! ^_^

Answer 31

knowing the graph of the functions would help a great deal, because a function passes the vertical line test

Answer 32

@nincompoop +1 But it also takes more time!

Answer 33

disagree, it is the easiest

Answer 34

@amrita000 remember the definition

Answer 35

$$\Huge y=f(x)$$

Answer 36

okiee :D

Answer 37

one x goes in and one y comes out

Answer 38

@nincompoop so she has trouble finding which of the expressions is not a function and she would be able to graph the last expression?

If she was able to graph it, she wouldn't need help to recognize it wasnt a function in my opinion

Answer 39

Anyway good job!

Answer 40

Graphs are great once the student understands the logical links the definition has to the graph.

Answer 41

Exactly!