Question

If A = `[(1, 12, 4y), (6x, 5, 2x), (8x, 4, 6)]` is a symmetric matrix, then (2x + y) is ______.

विकल्प

• −8

• 0

• 6

• 8

Answer 1

If A = `[(1, 12, 4y), (6x, 5, 2x), (8x, 4, 6)]` is a symmetric matrix, then (2x + y) is 8.

Explanation:

Given: A = `[(1, 12, 4y), (6x, 5, 2x), (8x, 4, 6)]` is a symmetric matrix

∴ A' = A

`[(1, 6x, 8x), (12, 5, 4), (4y, 2x, 6)] = [(1, 12, 4y), (6x, 5, 2x), (8x, 4, 6)]`

By the equality of matrices

6x = 12

x = `12/6`

∴ x = 2

4y = 8x

4y = 8 × 2

4y = 16

y = `16/4`

∴ y = 4

2x + y = 2(2) + 4

∴ 2x + y = 8