Which of the following is not a function?
a) y=3x^2-3 b) x=3y^2-3 c) y= 3√x, x=0

Question

Which of the following is not a function?
a) y=3x^2-3 b) x=3y^2-3 c) y= 3√x, x>=0

anonymous · Answer

they are all equations of a curve...

But it is probably B and D because they define X and not Y

anonymous · Answer

i was thinking it was b because all the other equations say y= and that's what i was taught....

geometry_hater · Answer

No just because it says x= doesn't mean it isn't an equation.

You could move Y over to the x side to get the y= part

anonymous · Answer

myeh...... then how do i find out which is the right one?

geometry_hater · Answer

If you could graph each one and if X repeats (The line would go over the same line twice) then it isnt a funtion

anonymous · Answer

....of all the times for my graphing calculator to be dead

geometry_hater · Answer

Online Graphing calculator

anonymous · Answer

o.o those exist?

geometry_hater · Answer

Yes

anonymous · Answer

thank you ^^ to google.

anonymous · Answer

no, x = 3y^2-3
is y = +sqrt(-3-x) or 
y = -sqrt(-3-x)

So no, y can't have two values for the same x.


I also suggest using graph.tk

geometry_hater · Answer

And personally i use this online graphing calculator https://www.desmos.com/calculator But i think there might be better ones

anonymous · Answer

wait...... using this calculator wasn't i right saying it wasn't x=3y^2-3? that doesn't pass the straight line test so it's wrong......?