# Cartesian equation of a plane

this is just a simple question

For a plane in vector form, can the cartesian equation (Ax+By+Cz+D=0) be found by finding the cross product of the two vectors? My understanding is that A, B and C are the components of the normal of the plane, which can be found by doing the cross product. However, upon comparing my answers to those of a classmate, I discovered our answers were different, he used a method of substitution/elimination.