Question

# If 3A = and A is orthogonal, then x + y =

- 3
- – 2
- –3
- None

## The correct answer is: –3

### A = A = B (Let)

and AA' = I

. = I

= B.B' = 9 I

. =

x + 4 + 2y = 0, 2x + 2 – 2y = 0

x = – 2, y = – 1

x + y = (–2) + (–1)

= –3

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