Y - X \ XY = - 4\5
5*(Y-X) = - 4XY
5Y - 5X = - 4XY
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X - Y = 4 ---> X = 4 + Y
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5Y - 5*(4+Y) = - 4*(4+Y)*Y
5Y - 20 - 5Y = (- 16 - 4Y)*Y
- 20 = - 16Y - 4Y^2
-4Y^2 - 16Y + 20 = 0
4*(-Y^2 - 4Y + 5) = 0
D = 16 - 4*(-1)*5 = 16 + 20 = 36
V D = 6
Y1 = 4 + 6 \ -2 = 10\-2 = -5
Y2 = 4 - 6 \ - 2 = - 2\-2 = 1
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X = 4 + Y
X1 = 4 - 5 = - 1
X2 = 4 + 1 = 5
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Ответ X1 = - 1 Y1 = - 5
X2 = 5 Y2 = 1