Originally Posted by

**evouga** No... how did you get that equation? Where are the unknowns?

Carefully write down the three equations, then try to turn them into a matrix equation of the form Ax = b. If you show your steps I'll try to help in more detail.

The second question is very vague... are you looking for a geometric interpretation? An algebraic one?

The geometric picture will depend on the rank of the matrix formed by the three given vectors. You can determine the rank by trying to put it into row-echelon form. The span of the vectors will then form a linear subspace whose dimension is equal to the rank of the matrix: rank 1 gives you a line, rank 2 a plane, and full rank the entire space R^3. (x,y,z) is in the span if it lies in that subspace.