Question

College Algebra: reviewing for Final Exam!!
Which one of the following does not define y as a function of x?
A.) x^2+y=16
B.) y=(x-3)^2-1
C.) x+y=3
D.) x=y^2

Answer 1

@dan815 @freckles @jim_thompson5910 @Nnesha @TheSmartOne @triciaal
Any of you able to help me? :)

Answer 2

how far did you get?

Answer 3

No where. I don't even know where to start.

Answer 4

y as a function of x
means you have y = whatever

Answer 5

Oh. Is it always y=whatever?

Answer 6

if you solved one of those equations for y, you'll get y = plus/minus...

that will be the equation that is NOT a function because y = the plus form while it also equals the negative form. That means one x value could produce 2 y values

Answer 7

Rule: a relation is a function if every given x input produces EXACTLY ONE output y.

Answer 8

Hmmm

Answer 9

@Natasha.g.2013 @jim_thompson5910 last post is the formal way to say it

Answer 10

i already gave him the medal

Answer 11

He's right, I'm not saying he isn't. I was writing down the rule, so I wouldn't forget it.

Answer 12

So, the answer would be D.) x=y^2 because it can only produce 1 y

Answer 13

he is a very reliable source

Answer 14

Thank you very much @jim_thompson5910 and @triciaal for helping me! :)

Answer 15

the answer is x = y^2 because solving for y gives you y = plus/minus sqrt(x)

so y is either y = sqrt(x) or it is y = -sqrt(x)

Answer 16

Woohoo!! :)

Answer 17

if x = 4, then y is either +2 or -2

so that is one example showing how it's not a function

Answer 18

You're right! :)

Answer 19

go and ace that test !

Answer 20

Thank you!!!! :)