I have 2 questions:
The yz-plane has a simple basis, namely, {(0,1,0), (0,0,1)}. Take a point p in the plane you are looking for. Then p - (6,1,0) must lie on the yz-plane, i.e. it must be a linear combination of the basis. Therefore,
p - (6,1,0) = λ(0,1,0) + μ(0,0,1)
or
p = λ(0,1,0) + μ(0,0,1) + (6,1,0)
where λ and μ are the parameters.
Note that the representation is not unique because it depends on the basis chosen for the yz-plane. A different basis would require different values for the parameters.