If A=125311421, find A−1. Hence solve the system of equationsx+3y+4z=8,2x+y+2z=5,5x+y+z=7.Answer: x=1, y=1, z=1SolutionHere ∣A∣=−1(1)−3(2−10)+4(2−5)=−1+24−12=11=0. From the cofactors,adjA=−18−31−191426−5,A−1=111adjA.With B=857, X=A−1B=111.x=1, y=1, z=1CBSE Class 12 Board · Subjective