Question

Решите систему уравнений : х+2у+3z=5;2x-y-z=1;x+3y+4z=6

Answer 1

 x + 2y + 3z = 5 
2x - y - z = 1 
x + 3y + 4z = 6 
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- x - 3y - 4z = - 6 
- y - z = - 1 
y = 1 - z
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2x - y - z = 1 
2x = 1 + y + z 
2x = 1 + 1 - z + z 
2x = 2 
x = 1 
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x + 2y + 3z = 5 
1 + 2( 1 - z ) + 3z = 5 
1 + 2 - 2z + 3z = 5 
z = 5 - 3 
z = 2 
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y = 1 - z 
y = 1 - 2 
y = - 1 
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ОТВЕТ x = 1 ; y = - 1 ; z = 2