Срочноооооо!!!!!!!!!!!!!!!1
X=9-y. (9-y)^2-y^2=72 81-18y+y^2-y^2=72 81-18y=72, -18y=-9, y=0.5, x=9-0.5, x=8.5 проверяем 8.5^2-0.5^2=72 72.25-0.25=72 8.5+0.5=9 9=9