5) x – y + 2z = 9 x – 2y + 3z = 1 2x - 2y – z = 15 Tentukan nilai x, y dan z ?

x - y + 2z = 9 ---(1)
x - 2y + 3z = 1 ---(2)
2x - 2y - z = 15 ---(3)
[Jawab]
(1) × 2 = 2x - 2y + 4z = 18 ---(1)'
(2) - (1)' = - x - z = -17 ---(4)
(2) - (3) = - x + 4z = - 16 ---(5)
-------------------- -
-5z = -1
z = 1/5
Masukan ke (4)
- x - 1/5 = - 17
- x = - 85/5 + 1/5
- x = -84/5
x = 84/5
Masukan ke (1)
84/5 - y + 2/5 = 9
-y = 9 - 2/5 - 84/5
-y = 45/5 - 2/5 - 84/5
-y = 42/5 - 84/5
-y = - 42/5
y = 42/5
Jadi (x,y,z) = (84/5,42/5,1/5)
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Maaf kalo jawabnya salah