Salut! =)
1 )
x / y = 7 / 9
x - y = 6
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x , y = ?
7y = 9x
x = 7y / 9
Inlocuim in a doua formula
7y / 9 - y = 6 ( Aducem la acelasi numitor )
7y - 9y = 54
-2y = 54
y = -27
x = -21
2 )
a / 2 = b / 4 = c / 6
a + 2c = 7
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a , b , c =?
a / 2 = c / 6 => a = c / 3
Inlocuim in a doua formula
c / 3 + 2c = 7 ( Aducem la acelasi numitor )
c + 6c = 21
7c = 21 => c = 3
a = c / 3 => a = 1
a / 2 = b / 4
1 / 2 = b / 4 => b = 2
Bafta! =)
