2020-07-03 08:21:16 -0600 received badge ● Popular Question (source) 2019-02-09 20:02:25 -0600 commented question Is there an easy way to get the matrix of coefficients from a product of a matrix and a vector? Ok, I should have used the word "rewrite" instead of "get" in my question. 2019-02-09 19:58:28 -0600 commented question Is there an easy way to get the matrix of coefficients from a product of a matrix and a vector? Sorry, I wasn’t clear. I didn’t mean to ask to solve the equation in general. What I was wondering is if there is a simple function that just returns the matrix of coefficients ai,j in front of the xi’s. Just a purely formal exercise. In other words, just have the computer do the rewriting (splitting) B in the form of A x. Nothing else. Yes, I know, I could write a function myself, but maybe someone already did it. According to the answer on Stackexchange, it can be done easily in Mathematica. 2019-02-09 12:59:57 -0600 received badge ● Student (source) 2019-02-08 17:11:11 -0600 asked a question Is there an easy way to get the matrix of coefficients from a product of a matrix and a vector? I have a matrix multiplication of the form $$B = A x$$ or $$\begin{pmatrix} a_{11} x_1 + a_{12} x_2 + a_{13} x_3 \\ a_{21} x_1 + a_{22} x_2 + a_{23} x_3 \\ a_{31} x_1 + a_{32} x_2 + a_{33} x_3 \end{pmatrix} = \begin{pmatrix} a_{11} & a_{12} & a_{13}\\ a_{21} & a_{22} & a_{23}\\ a_{31} & a_{32} & a_{33} \end{pmatrix} \cdot \begin{pmatrix} x_1 \\ x_2 \\ x_3 \end{pmatrix}$$ Is there a way in Sage to factor $B$ in a way where I give it $x$ and it returns $A$? Edited from a question posted by someone else at the Mathematica Stackexchange