This isn't really a particular question...i just missed the classes relating to these 2 topics so I have no idea how to do questions with them....so can someone please explain how i go about solving questions such as: 1. I'm given 3 points in R3, and i'm supposed to find the equation of the plane that passses through them. How do I go about doing this? 2. I am given a matrix and I'm supposed to express it as a product of elementary matrices. I asked abotu this here before, but I think i didn't understand it properly because I had a question like this on my midterm and I definitely got it wrong. I know I am supposed to reduce it to reduced row echelon form and keep track of the steps i take in the process. But then, what do i do with those steps? I know its not as simple as applying the same steps to a set of identity matrices of the same size...there's some kind of other trick to it.