The plane [tex]x+4y+z=6[/tex] has normal vector [tex]\vec n = \vec\imath+4\,\vec\jmath+\vec k[/tex]. Any line perpendicular to this plane is parallel to [tex]\vec n[/tex]. The one that passes through the origin is [tex]\vec n\,t[/tex], where [tex]t\in\Bbb R[/tex]. Translate this line by the vector [tex]\vec\imath+6\,\vec k[/tex] to get the line we want,
[tex]\vec r(t) = \vec n\,t + \vec\imath + 6\,\vec k = (t+1)\,\vec\imath + 4t\,\vec\jmath + (t + 6)\,\vec k[/tex]
In parametric form, we have
[tex]\begin{cases} x(t) = t + 1 \\ y(t) = 4t \\ z(t) = t + 6 \end{cases}[/tex]