[질문] x+y=-1,x세제곱+y세제곱=8 (x-y)제곱 풀어주세요

x세제곱+y세제곱=(x+y)(x 제곱-xy+y제곱)=8 x제곱- xy+y제곱=-8=(x+y)제곱-3xy xy=3 (x-y)제곱=(x+y)제곱-4xy=1-12=-11 제곱인데음수가나오네요~답은맞아요