Ответ:

y₁=4   x₁=8

y₂=24  x₂= -12

Объяснение:

xy/x-y=8    x≠y

x+y=12

x=12-y

(12-y)y/(12-y-y)=8

(12y-y²) / (12-2y) = 8

12y-y² =8* (12-2y)

12y-y² = 96 - 16y

12y-y² - 96 + 16y=0

-y²+28y-96=0

y²-28y+96=0

D = b² - 4ac = (-28)² - 4·1·96 = 784 - 384 = 400

√D=√400=20

y₁=(28 - 20)/ 2  =   8 /2  = 4

y₂=(28 + 20)/ 2  =   48 /2  = 24

y₁=4   x₁=12-4=8

y₂=24  x₂=12-24= -12