-8у+х=1

у²-х=8

-у(8-у)=9

-8у+у²-9=0

у²-8у-9=0

D=64-4*(-9)=64+36=100=10²

х = 8±10 / 2 = -2/2; 18/2 = -1; 9.

-8у=1-х

-8у=1-(-1)

-8у=2

у=-1/4 = -0.25

-8у=1-9

-8у=-8

у=1

ответ: (-1; -0.25), (9; 1).