\((8\)分\()\)阅读材料:若
\(m\)\({\,\!}^{2}-2\)
\(mn\)\(+2\)
\(n\)\({\,\!}^{2}-2\)
\(n\)\(+1=0\),求
\(m\)、
\(n\)的值.
解:\(∵\)\(m\)\({\,\!}^{2}-2\)\(mn\)\(+2\)\(n\)\({\,\!}^{2}-2\)\(n\)\(+1=0\),\(∴(\)\(m\)\({\,\!}^{2}-2\)\(mn\)\(+\)\(n\)\({\,\!}^{2})+(\)\(n\)\({\,\!}^{2}-2\)\(n\)\(+1)=0\)
\(∴(\)\(m\)\(-\)\(n\)\()^{2}+(\)\(n\)\(-1)^{2}=0\),\(∴(\)\(m\)\(-\)\(n\)\()^{2}=0\),\((\)\(n\)\(-1)^{2}=0\),\(∴\)\(n\)\(=1\),\(m\)\(=1\).
根据你的观察,探究下面的问题:
\((1)\)已知\(x\)\({\,\!}^{2}+2\)\(xy\)\(+2\)\(y\)\({\,\!}^{2}+2\)\(y\)\(+1=0\),求\(x\)、\(y\)的值;
\((2)\)已知\(a\),\(b\),\(c\)是\(\triangle \)\(ABC\)的三边长,满足\(a\)\({\,\!}^{2}+\)\(b\)\({\,\!}^{2}= 12\)\(a\) \(+8\)\(b\)\(-52\),且\(\triangle \)\(ABC\)是等腰三角形,求\(c\)的值.