\det= \left|\begin{array}{ccc}1&2&1\\ 3&-5&3\\ 2&7&-1\end{array}\right|= 5+12+21+10+6-21=33\\ \\ \\ \det(X)= \left|\begin{array}{ccc}4&2&1\\1&-5&3\\8&7&-1\end{array}\right|=20+48+7+40+2-84=33\\ \\ \\ \det(Y)= \left|\begin{array}{ccc}1&4&1\\ 3&1&3\\2&8&-1\end{array}\right|=-1+24+24-2+12-24=33\\ \\ \\ \det(Z)= \left|\begin{array}{ccc}1&2&4\\3&-5&1\\2&7&8\end{array}\right|=-40+4+84+40-48-7=33X = det(X)/det = 1Y = det(Y)/det = 1Z = det(Z)/det = 1Ответ: (1;1;1).