for which of these equations is y a function of x?

y=3x^3
xy=1
y^2=x
y^3=8x

Question

for which of these equations is y a function of x?

y=3x^3
xy=1
y^2=x
y^3=8x

anonymous · Answer

I'm not really sure how to answer this. Any of these y could be a function of x except the x = y^2 one because there's 2 possible outputs for the same input.

anonymous · Answer

k thanks

anonymous · Answer

Y is a function of x if for e given x there is only one corresponding y.
y=3x^3 is OK
xy=1 => y=1/x is OK
y^2=x => $$y = \sqrt{x}$$ is OK
y^3=8x =>$$y = \sqrt[3]{8x}$$ is OK

You can graph these functions and when you draw a vertical line from any x value the line should intersect the graph in only one point. (only one y value for each x)

anonymous · Answer

$y^2 = x \implies y  = \pm \sqrt{x} $ 
Therefore it is not a function because for any one value for x, you have 2 possible values for y.

anonymous · Answer

My mistake it is a function for x$$X \ge 0$$

anonymous · Answer

Ok one more try it is a function if the function range is 
$$Y \ge 0$$