Question

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x+2y + 4z=6,2x + 4y+z=17,3x + 2y - 9z=2
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Answer 1

Answer:

x + 2y + 4z = 6 --- 1

2x + 4y + z = 17 --- 2

3x + 2y - 9z = 2 --- 3

1×2---- 2x + 4y + 8z = 12

2 ------ 2x + 4y + z = 17

7z = -5

z = -5/7

1 --- x + 2y + 4z = 6

3 --- 3x + 2y - 9z = 2

2x + 13z = 4

2x + 13(-5/7) = 4

2x - (65/7) = 4

2x = 4+65/7

x = 5

3 --- 3x + 2y - 9z = 2

3(5) + 2y - 9(-5/7) = 2

15 + 2y + 14/7 = 2

15 + 2y + 2 = 2

15 + 2y = 2-2

15 + y = 0/2

y = -15

x = 5; y = -15; z = -5/7