If A=[3−1−42], find a matrix B such that AB=I.Answer: B=A−1=[121223]SolutionAB=I means B=A−1. For a 2×2 matrix, A−1=∣A∣1[d−c−ba] with ∣A∣=(3)(2)−(−4)(−1)=2.B=21[2143]=[121223].CBSE Class 12 Board · 2006 · Subjective