1. The problem statement, all variables and given/known data Suppose that a straight line L1 passes through the point (2, 1, 2), and is perpendicular to another line which is given by L2(t) = (1 + t, 2 + t, 3 - t); -inf < t < inf Suppose that L1 and L2 intersects at a point (a, b, c): Find (a, b, c): 2. Relevant equations Dot product (which equals 0 for perpendicular lines) 3. The attempt at a solution I've tried quite a few solutions but I get the feeling I'm making this WAY more complicated than is necessary. The trouble is my teacher explained some method of getting a plane out of the given line and then using the plane's normal vector to find L2 and then determining the intersection, but I can't for the life of me figure out what he did. At this point I'm not even sure where to start. I attempted to do some projection of vectors from a point on the given line to the point that L1 passes through. However I get stuck after that point at figuring out what to do. I would appreciate any help! Thanks!