Beta, first you find the matrix of cofactors, but careful — signs alternate like a chessboard, starting with plus for the (1,1) entry. Then transpose that to get the adjoint, and divide by the determinant. Honestly, I keep a marked diagram of the plus-minus grid next to my sewing machine at home, to check the signs while studying. My Ma says solving matrices is like aligning silk panels: one flipped sign and the whole pattern, I mean solution, goes *ulta-pulta*!
#javelin#throws
Jump in to reply — no account needed.