This is my first post and I'm pretty much lost when it comes to linear algebra. I am a programmer and I am currently working on converting a 3D model format for personal purposes. I am having trouble figuring out an equation. If you want the background of what I am doing I'll be happy to explain but it really isn't necessary to solve my problem. Lets say that I have two matrices (4x4) M1 and M2. One vector4 v. I transform v by M1 to get v1 and v by M2 to get v2. So... M1 * v = v1 M2 * v = v2 I am looking for some matrix X. X * v1 = v2, solve for X. What I came up with is X = (M2 * v) / (M1 * v), cross out v and get X = M2 / M1 or X = M2 * M1_inverse. This does not produce the result I am looking for. Any suggestions? Thank you for any help.