If Z = diag[a,b,c], then we can write it as

So, A+2B

=diag[4,9,37]

Conclusion: A + 2B = diag[4,9,37]

(Given answer is wrong)

ii. B + C – A

If Z = diag[a,b,c], then we can write it as

B+C-A

= diag[-1,6,8]

Conclusion: B+C-A = diag[-1,6,8]

iii. 2A + B – 5C

If Z = diag[a,b,c], then we can write it as

2A+B-5C

= diag[-19,27,17]

Conclusion: 2A + B – 5C = diag[-19,27,17]

(Given answer is wrong)