# How do you use the vertical line test to show x-y^2=0 is a function?

You can not use the vertical line test to show that $x - {y}^{2} = 0$ is a function because it is not a function
Graph for $x - {y}^{2} = 0$:
For all $x > 0$ a vertical line crosses the line of the equation in two places and therefore the equation does not represent a function.