If  show that  Hence find 

For the matrix  show that A² – 4 A + 7 I = O. Hence obtain A^–1.

Show that the matrix  satisfies the equation A² – 4A + I = O and hence find A^–1.

If   show that A² – 5A + 7 I = O. Hence find A ^–1.

For the matrix  find the numbers a and b such that A² + aA + bI = O. Hence find A^–1.

186. If A is square matrix such that A³ = I, prove that A is non-singular and find adj. A and prove that A^–1 = A².

If 

Find the inverse of the matrix  and show that a A ^-1 = (a² + b c + 1) I – a A.

If 
verify (AB)^–1 = B ^–1 A^–1