Make sure you are confident in calculating with negative numbers, which is a skill often needed to solve equations. To solve the equation, do the inverse operation. The inverse of multiplying by 12 is ...

SIAM Journal on Applied Mathematics, Vol. 31, No. 4 (Dec., 1976), pp. 579-585 (7 pages) Necessary and sufficient conditions for existence and expressions for general Hermitian and nonnegative definite ...

A numerical solution of the quadratic matrix equations associated with a nonsingular M-matrix by using the alternately linearized implicit iteration method is considered. An iteration method for ...