Question

if A is a square mayrix such that A2 =A then(1+A)2-3Ais​

Answer 1

Answer:

Given A

2

=A

Consider, (I+A)

3

−7A=I

3

+A

3

+3I

2

A+3IA

2

−7A

=I+A

2

+3A+3A−7A

=I+7A−7A

⇒(I+A)

3

−7A=I