I am a little bit confused about these 2. A vector equation goes like this: x1v1+x2v2+...+xnvn=b and Matrix equation goes like this: Ax= [v1 v2 .. vn][x1 x2 . . . xn] v is a vector in the vector equation, but in the matrix equation x becomes the vector and v is just the matrix. My question is, why does it get switched like this?