If show that A 2 – 5A + 7I =0.

Question

Philoid · Accepted Answer

To prove: A² – 5A + 7I = 0

Given: A =

L.H.S: A² – 5A + 7I

R.H.S = 0

I =

Calculating value of A²:

A² = A.A

=

Substituting value in L.H.S we get,

= A² – 5A + 7I

.

= 0 = R.H.S

L.H.S = R.H.S

Hence A² – 5A + 7I = 0 is proved.