The matrix A is a square matrix of the coefficients on the left side of the mesh equations, X is a column matrix of the unknown mesh currents, and B is a column matrix of the input voltages on the right side of the mesh equations. To solve this matrix equation we multiply by the inverse of the coefficient matrix (A On the left side the result is A Ax X, and the right side becomes A B. In other words, multiplying by A yields the solution for the unknown mesh currents as