-5y² + 7xy = 1 |*3
2y - 3xy = 0 |*7
--
-15y² + 21xy = 3
14y - 21xy = 0 |+
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-15y² + 14y = 3
===
15y² - 14y + 3 = 0
2y - 3xy = 0
D = 14² - 4*15*3 = 196 - 180 = 16
y12 = (14 +- 4)/30 = 1/3 3/5
1. y = 1/3
2*1/3 - x = 0
x = 2/3
2. y = 3/5
2*3/5 - 3*3/5х = 0
9/5х = 6/5
х = 6/9 = 2/3
ответ (2/3, 3/5) (2/3, 1/3)
хотя лечге из второго
2y - 3xy = 0
y(2 - 3x) = 0
y = 0
x = 2/3 итд
