1.
\((1)\sqrt{49}=\)______,\(16\)的算术平方根是______,\(-8\)的立方根是_________.
\((2)\)已知二元一次方程\(2x-3y=5\),用含\(y\)的式子代数式\(x\)为_______.
\((3)\)已知点\(A(-1,b+2)\)在\(x\)轴上,则\(b=\)_______.
\((4)\)如图,已知直线\(AB\),\(CD\)相交于点\(O\),\(OE⊥AB\),\(∠EOC=28^{\circ}\),则\(∠BOD=\)_______度.
\((5)\)已知方程\(3x^{m-1}–2y^{n}=7\)是关于\(x\)、\(y\)的二元一次方程,则\(mn=\)__________.
\((6)\)已知\(\begin{cases} & x=2 \\ & y=1 \end{cases}\)是二元一次方程组\(\begin{cases} mx{+}ny{=}8 \\ {nx}{-}my{=}1 \end{cases}\)的解,则\(m+3n\)的值是__________.
\((7)\)若\(x\),\(y\)为实数,且满足\(\left| {{x}^{2}}-9 \right|+\sqrt{y+3}=0\),则\(x-y=\)________.
\((8)\)如果不等式组\(\begin{cases} x{-}3{ > }0 \\ {-}x{+}m{ > }0 \end{cases}\)无解,那么\(m\)的取值范围是__________.