SOLUTION: 4x=y^2 how do i determine if this equation defines y as a function of x? thank you

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Question 910385: 4x=y^2 how do i determine if this equation defines y as a function of x?
thank you
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

4x=y%5E2 does not define y as a function of x, because some value(s) of x have more than one y.
In general,
4x=y%5E2 =>y=sqrt%284x%29 or y=-sqrt%284x%29
=>+y=2sqrt%28x%29+ or y=-2sqrt%28x%29
So, all the values of x larger than +0+ would have two y values.
For example, x=16 would be paired with y=2%2A4=8+and+%7B%7B%7By=-8
A function cannot assign more than one y+to any x value.