Once you find the line r passing through A(1,2,0) and B(1,0,2). Find the line s passing by (-2,0,0) perpendicular and secant to r.
Use the matrix approach.

Finding r:

AB(vector) = (0,2,-2)

$$\left[\begin{matrix}x-1 & y-2 & z \ 0 & 2 & -2\end{matrix}\right] = 0$$

So the line r is:

x-1/2 = 0
2y+2z-4 = 0.

Now I am stuck with the other point. I think I have to think something with planes but I am not sure, any hints?

Question

Once you find the line r passing through A(1,2,0) and B(1,0,2). Find the line s passing by (-2,0,0) perpendicular and secant to r.
Use the matrix approach.

Finding r:

AB(vector) = (0,2,-2)

$$\left[\begin{matrix}x-1 & y-2 & z \ 0 & 2 & -2\end{matrix}\right] = 0$$

So the line r is:

x-1/2 = 0
2y+2z-4 = 0.

Now I am stuck with the other point. I think I have to think something with planes but I am not sure, any hints?