8.
\((1)\)若盈利\(50\)万元记作\(+50\)万元,那么亏损\(20\)万元可记作:_____万元.
\((2)\)四边形内角和___________\({\,\!}^{\circ}\).
\((3)\)已知\(∠A\)的两边与\(∠B\)的两边分别平行,且\(∠A\)比\(∠B\)的\(3\)倍少\(40^{\circ}\),那么\(∠A=\)_____\({\,\!}^{\circ}\).
\((4)\)如图,已知\(AE/\!/DF\),则\(∠A+∠B+∠C+∠D=\)_____.
\((5)\)如图,在\(\triangle ABC\)中,\(∠ADC=110^{\circ}\),\(AD\)、\(CD\)分别平分\(∠BAC\),\(∠ACB\),则\(∠ABC=\)_____.
\((6)\)对于实数\(a\),\(b\),\(c\),\(d\),规定一种数的运算:\(\begin{vmatrix}a & b \\ c & d\end{vmatrix} =ad-bc\),那么当\(\begin{vmatrix}2 & 4 \\ -3 & x\end{vmatrix} =10\)时,\(x=\)_____.