Here is a picture of the problem. Can anyone give me some hints on the problem? I've looked in my textbook, but I don't know what "s" means. I found stuff on the parametric vector form, and it gives me the equation x = su + tv, but I don't see any "t"'s in this problem. I first tried setting up an augmented matrix with [ 1 1 0 0 | -3 ] [ 0 1 1 0 | -3 ] [ 0 0 1 1 | -4 ] [ 1 0 0 1 | -4 ] And I solved for the four variables, like: x1 = -3 - x2 x2 = -3 - x3 x3 = -4 - x4 x4 = -4 - x1 And now I'm stumped. I didn't think these would do anything, but setting the first and second rows equal to each other, and the third and fourth rows equal to each other simply gets x1 - x3 = 0 for both of them. I didn't think this would do anything either, but I tried also back substituting the x1 equation into the x4 equation, and then the x2 equation into x4, and so on, and that ended up with x4 = x4.