Если x+3y+5z=200 и x+4y+7z=225, тогда x+y+z=

Если x+3y+5z=200 и x+4y+7z=225, тогда x+y+z=
- Предмет:
  Алгебра
- Автор:
  lexus
- 6 лет назад

Ответы 1

х + 3у + 5z = 200x +4y + 7z = 225Отнимем из второго уравнения первое,получим:х - х + 4у - 3у + 7z - 5z = 225 - 200y + 2z = 25y = 25 - 2z → подставим значение у в первое уравнение: х + 3(25 - z) + 5z = 200 x + 75 - 3z + 5z = 200 x + 2z = 200 - 75 x = 125 - 2z → подставим значение х и у во 2-ое уравнение: 125 - 2z + 4(25 - 2z + 7z = 225 125 - 2z + 100 - 4z + 7z = 225 z = 225 - 100 - 125 z = 0y = 25 - 2zy = 25 - 0y = 25x = 125 - 2zx = 125x + y + z = 25 + 125 + 0 = 150
- Автор:
  pixie32
- 6 лет назад
- 0
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Если x+3y+5z=200 и x+4y+7z=225, тогда x+y+z=

Ответы 1

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