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 ...

One of the fundamental operations in machine learning is computing the inverse of a square matrix. But not all matrices have an inverse. The most common way to check if a matrix has an inverse or not ...