设向量\(\overrightarrow{a}=\left(\sin x, \sqrt{3}\cos x\right), \overrightarrow{b}=\left(-1,1\right), \overrightarrow{c}=\left(1,1\right) .(\)其中\(x∈[0,π])\)
\((1)\)若\(\left( \overrightarrow{a} \overrightarrow{b}\right)/\!/ \overrightarrow{c} \),求实数\(x\)的值;
\((2)\)若\(\overrightarrow{a}· \overrightarrow{b}= \dfrac{1}{2} \),求函数\(\sin \left(x+ \dfrac{π}{6}\right) \)的值.