27.(2023•沈阳三模)已知a→=(1,2)\overrightarrow{a}=(1,2)a=(1,2),b→=(x,4)\overrightarrow{b}=(x,4)b=(x,4),若a→\overrightarrow{a}a与b→\overrightarrow{b}b的夹角是锐角,则实数xxx的取值范围是 ___(−8(-8(−8[,]2)⋃(22)\bigcup (22)⋃(2[,]+∞)+\infty )+∞)___.