Salut! =)
x - y = 36
x / y = 5 / 7
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x , y = ?
x / y = 5 / 7 => 7x = 5y => x = 5y / 7
Inlocuim in prima formula :
5y / 7 - y = 36
Aducem la acelasi numitor :
5y - 7y = 252
-2y = 252
y = - 126
x = -90
Proba : -90 - ( - 126 ) = -90 + 126 = 36 ( corect )
Bafta! =)