6.
\((1)\)八边形的内角和是__________.
\((2)\)当\(x=\)_______时,\(2x-3\)与\(\dfrac{5}{4x+3}\)的值互为倒数.
\((3)\)整式\((2x)^{n}-81\)分解因式后得\((4x^{2}+9)(2x+3)(2x-3)\),则\(n\)的值是_____.
\((4)\)已知\({{(x+y)}^{2}}=2\),\({{(x-y)}^{2}}=1\),则\({{x}^{3}}y+x{{y}^{3}}\)的值为__________ .
\((5)\)如图,四边形\(ABCD\)中,\(AD=CD=b\),\(AB=CB=a\),我们把这种两组邻边分别相等的四边形叫做“筝形”\(.\)已知\(\angle BAD\)的角平分线交\(BD\)于\(E\)点,若\(AC=m\),\(BD=n\),则\(E\)到\(AB\)的距离为__________\( .(\)用\(m\)、\(n\)、\(a\)、\(b\)表示\()\)
\((6)\)如图,在\(\triangle ABC\)中,\(∠B=30^{\circ}\),点\(D\)是\(BC\)的中点,\(DE⊥BC\)交\(AB\)于点\(E\), 点\(O\)在\(DE\)上,\(OA=OC\),\(OD=2\),\(OE=5\),则\(AE\)的长为 ______.