Question

Determine the value of x + y if `[(2x + y, 4x),(5x - 7, 4x)] = [(7, 7y - 13),(y, x + 6)]`

Answer 1

`[(2x + y, 4x),(5x - 7, 4x)] = [(7, 7y - 13),(y, x + 6)]`

⇒ 2x + y = 7  .......(1)

4x = 7y – 13   .......(2)

5x – 7 = y   .......(3)

4x = x + 6   .......(4)

From (4)

4x – x = 6

3x = 6 

⇒ x = `6/3` = 2

Substituting x = 2 in (1), we get

2(2) + y = 7

⇒ 4 + y = 7

⇒ y = 7 – 4 = 3

So x = 2 and y = 3

∴ x + y = 2 + 3 = 5