1. The problem statement, all variables and given/known data Find the equation of the plane through the line of intersection of the planes x-z=1 and y+2z=3 AND perpendicular to the plane x+y-2z=1 2. Relevant equations The normal of the first plane is n1=(1,0,-1), second is n2=(0,1,2) 3. The attempt at a solution I started off by finding the cross product of the intersecting planes, which is (1,2,1). I think this vector is the direction vector of the line that defines the intersection of the two planes. So I think this vector has to be ON the plane (THE plane who's equation we're trying to find). But now I'm not sure where to go from here. Since my plane has to be parallel to the third plane, I guess that the normal for that plane would be the normal for my plane. So I have to normal.....I need points..... I'm guessing this is an easy question, but I've just mixed myself up a lot!