Suppose A is a non-singular matrix such that A3ā3A2+6AāI=0. Then, Aā1=___
A3−3A2+6A
A2−3A+6I
A2+3A−6I
A3+3A2+6A
A3−3A2+6A−I=0 ⇒A3−3A2+6A=I Pre-multiply the equation by A−1 A−1A3−3A−1A2+6A−1A=A−1⇒(A−1A)A2−3(A−1A)A+6(A−1A)=A−1⇒A−1=A2−3A+6I [∵A−1A=I]
Suppose A is a non-singular matrix such that A3−3A2+6A−I=0. Then, A−1=___