已知函数\(f(x)=\sqrt{2}(\sin x+\cos x)\cos x-\dfrac{\sqrt{2}}{2}\).
\((\)Ⅰ\()\)用五点法作出函数\(f(x)\)在\(x∈[-\dfrac{\pi }{8},\dfrac{7\pi }{8} ]\)上的简图\((\)要求列表\()\);
\((\)Ⅱ\()f({{x}_{0}})=-\dfrac{3}{5}\),且\(x_{0}∈(\dfrac{3\pi }{8},\dfrac{5\pi }{8})\),求\(f({{x}_{0}}+\dfrac{\pi }{6})\)