Q. 225.0( 2 Votes )

# Show that satisfies the equation x^{2} – 3A – 7 = 0. Thus, find A ^{– 1}.

Answer :

A =

A^{2} =

=

Now, A^{2} – 3A – 7 = 0

=

=

=

So, A^{2} – 3A – 7I = 0

Multiply by A ^{– 1} both sides

= A.A. A ^{– 1} – 3A. A ^{– 1} – 7I. A ^{– 1} = 0

= A – 3I – 7A ^{– 1} = 0

= 7A ^{– 1} = A – 3I

= A ^{– 1} =

Hence, A ^{– 1} =

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