х+3у=4,
х²+2ху−у² =2
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х=4 - 3y
(4 - 3y)² + 2y(4 - 3y) - y² = 2
16 - 24y + 9y² + 8y - 6y² - y² - 2 = 0
2y² - 16y + 14 = 0
y² - 8y + 7 = 0
D = 64 - 28 = 36
y12 = (8 +- 6)/2 = 1 7
y1 = 1 x1 = 4 - 3*1 = 1
y2 = 7 x2 = 4 - 3*7 = -17
ответ (1,1) (-17, 7)
