已知向量\(\overrightarrow{a}=\left( 1,2 \right),\overrightarrow{b}=\left( x,1 \right),\overrightarrow{c}=\left( 1,y \right).\)
\((\)Ⅰ\()\)若\(\overrightarrow{a}/\!/\left( \overrightarrow{b}-\overrightarrow{c} \right)\),求\(x,y\)满足的关系式;
\((\)Ⅱ\()\)在\((\)Ⅰ\()\)成立的条件下,且有\(\overrightarrow{a}\bot \left( \overrightarrow{b}+\overrightarrow{c} \right)\),求\(x,y\)的值.