9.
\((1)\)函数\(f\)\((\)\(x\)\()=-\)\(x\)\({\,\!}^{2}+2\)\(x\)\(+3\)在区间\([2,3]\)上的最大值为________.
\((2)\)函数\(y={{3}^{x-4}}+b\)图象恒过定点\((4,6)\),则\(b=\) .
\((3)\)已知函数\(f(x)=\begin{cases}4x-6,x < 2 \\ {x}^{2}-2ax,x\geqslant 2\end{cases} \) 是\(R\)上的增函数,则实数\(a\)的取值范围是 .
\((4)\)已知\(f\)\((\)\(x\)\()\)在\(R\)上是奇函数,且满足\(f\)\((\)\(x\)\(+4)=\)\(f\)\((\)\(x\)\()\),当\(x\)\(∈(0,2)\)时,\(f\)\((\)\(x\)\()=2\)\(x\)\({\,\!}^{2}\),则\(f\)\((7)=\)________.