Why is the plane x=2/5 crossing the y-axis instead of the x-axis? Why is the plane x=2/5 crossing the y-axis instead of the x-axis? I thought it would be opposite like when you graph a line. Would the vector be (.4,0,0)

I'm not familiar with your software, but geometrically the plane $x=2/5$ should cross the $x$ axis, and only the $x$ axis, at the point $(2/5,0,0)$. The values of $y$ and $z$ can be anything, but the plane never crosses either the $y$ or $z$ axes, because that would require $x=0$.
