Verified answer

x^2+xy=8

2x+y=6

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x(x+y)=8

x+y=6 - x

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x(6 - x) = 8

6x - x^2 = 8

x^2 - 6x + 8 = 0

D = 36 - 32 = 4    

x12 = (6+-2)/2 = 2   4

y = 6 - 2x

x1 = 2  y1 = 6 - 2*2 = 2

x2 = 4  y2 = 6 - 2*4 = -2

ответ (2, 2) (4,-2)