Răspuns:
2x + y = 3
- x + 4y = 21 |×2
2x + y = 3
-2x + 8y = 42
adunam relatiile
2x - 2x + y + 8y = 3 + 42
9y = 45
y = 5
inlocuim y
2x + 5 = 3
2x = 3 - 5
2x = - 2
x = - 1
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- 2x + 3y = 1 |×3
3x - 4y = - 1 |×2
- 6x + 9y = 3
6x - 8y = - 2
adunam relatiile
- 6x + 6x + 9y - 8y = 3 + (-2)
y = 1
inlocuim y
6x - 8 = - 2
6x = 8 - 2
6x = 6
x = 1
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x - 2y = - 5
3x + y = 6 |×2
x - 2y = - 5
6x + 2y = 12
adunam relatiile
x + 6x - 2y + 2y = 12 - 5
7x = 7
x = 1
inlocuim x
6 + 2y = 12
2y = 12 - 6
2y = 6
y = 3
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7x - 6y = 19
x - 2y = 5 |×(-7)
7x - 6y = 19
-7x + 14y = - 35
adunam relatiile
7x - 7x + 14y - 6y = 19 - 35
8y = - 16
y = - 2
inlocuim y
7x + 12 = 19
7x = 19 - 12
7x = 7
x = 1
