If A is a square matrix such that │A│≠0 and A2 – A + 2I = 0 then A-1=?

2 – A + 2I = 0

Multiplying by A-1


A-1A2 – A-1A + 2I A-1 = 0


A- I + 2 A-1 = 0


A-1=

1