Hello! (Wave)
If we want to find the equation of the plane that is perpendicular to the line $l(t)=(-1,-2,3)t+(0,7,1)$ and passes through $(2,4,-1)$.
If (x,y,z) is a point of the line then it is of the form (-t,-2t+7,3t+1).
We get that $t=-x=\frac{7-y}{2}=\frac{z-1}{3} \Rightarrow...