2.
填空题:
\((1)\)已知\({{x}^{n}}=2\),\({{y}^{n}}=3\),则\({{({{x}^{2}}y)}^{n}}=\)_______;
\((2)\)已知\(x-2y+1=0\),则\({{2}^{x}}\div {{4}^{y}}\times 8=\)________;
\((3)\)已知\(x+y=5\ ,\ {{x}^{2}}-{{y}^{2}}=20\ ,\)则\({{(x-y)}^{2}}=\)__________;
\((4)\)定义\(\left| \begin{matrix} & a\ \ \ b \\ & c\ \ \ d \\ \end{matrix} \right|=ad-bc\),若\(\left| \begin{matrix} & x-1\ \ \ \ 2-x \\ & 1-x\ \ \ \ x+2 \\ \end{matrix} \right|=8\),则\(x=\)_______。
\((5)\)已知:\({{x}^{2}}-2xy+{{y}^{2}}-6x+6y+9=0\),则\({{(x-y)}^{15}}\)的个位数字是______。