Question

Решите систему уравнений x/y +5y/x=-6 2x+7y=6

Answer 1

 X^2 / XY + 5Y^2 / XY = - 6XY 
X^2 + 5Y^2 = - 6XY 
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2X + 7Y = 6 
2X = 6 - 7Y 
X = 3 - 3,5Y 
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( 3 - 3,5Y)^2 + 5Y^2 = - 6Y*( 3 - 3,5Y) 
9 - 21Y + 12,25Y^2 + 5Y^2 = - 18Y + 21Y^2 
9 - 21Y + 17,25Y^2 = 21Y^2 - 18Y 
21Y^2 - 17,25Y^2 - 18Y + 21Y - 9 = 0 
3,75Y^2 + 3Y - 9 = 0 
D = 9 + 135 = 144 ; V D = 12
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Y1 = ( - 3 + 12 ) : 7,5 = 1,2 
Y2 = ( - 15) : 7,5 = ( - 2 )
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X = 3 - 3,5Y 
X1 = 3 - 4,2 = - 1,2 
X2 = 3 + 7 = 10 
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