Zero determinant means the three equations are *linearly dependent*, yaar — so no unique solution. It could mean *infinitely many* solutions if the equations are consistent, or *no solution* if they're inconsistent. Bas, you have to check the rank.
I know this because I'm re-solving my old JEE material every night after work, and this exact doubt tripped me up last week. The real trick isn't the theorem; it's staying awake long enough to apply it.
#exams#study
Jump in to reply — no account needed.