6.
已知三条直线\(l_{1}\):\(2x-y+a=0(a > 0)\),直线\(l_{2}\):\(-4x+2y+1=0\)和直线\(l_{3}\):\(x+y-1=0\),且\(l_{1}\)与\(l_{2}\)的距离是\(\dfrac{7\sqrt{5}}{10}\).
\((1)\)求实数\(a\)的值;
\((2)\)能否找到一点\(P\),使得\(P\)点同时满足下列三个条件:\(①P\)是第一象限内的点;\(②P\)点到\(l_{1}\)的距离是点\(P\)到\(l_{2}\)的距离的\(\dfrac{1}{2}\);\(③P\)点到\(l_{1}\)的距离与\(P\)点到\(l_{3}\)的距离之比是\(\sqrt{2}:\sqrt{5}\)?若能,求点\(P\)坐标;若不能,请说明理由.