5.
\((1)\)命题“存在 \(x > 1\),\(x^{2}+(m-3)x+3-m < 0\)”的否定是 ______ .
\((2)\)若命题“\(∃t∈R\),\(t^{2}-2t-a < 0\)”是假命题,则实数\(a\)的取值范围是 ______ .
\((3)\)过抛物线\(x^{2}=8y\)焦点\(F\)作直线\(l\)交抛物线于\(A\)、\(B\)两点,若线段\(AB\)中点\(M\)的纵坐标为\(4\),则\(|AB|= \)______ .
\((4)\)已知双曲线\(\dfrac{{{x}^{2}}}{m+2}-\dfrac{{{y}^{2}}}{m+1}=1\)的离心率为\(\dfrac{\sqrt{7}}{2}\),则\(m= \)______ .