The?number?of?integer?solutions?for?the?syetem?of?inequalities??about?x?is?just?6,then?the?range?of?value?for?real?number?a?is
(integersolutions整数解;syetem of inequalities不等式组;the range of value取值范围)A.-2.5<a≤-2B.-2.5≤a≤-2C.-5<a≤-4D.-5≤a≤-4
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A
解析分析:根据不等式的性质求出不等式的解集,根据不等式的解集找出不等式组的解集,根据已知得到-5<2a≤-4,求出即可.
解答:,解①得:x≥2a,解②得:x<2,∴不等式组的解集是2a≤x<2,∵不等式组的整数解有6个,∴-5<2a≤-4,∴-2.5<a≤-2.故选A.
点评:本题考查了解一元一次不等式(组)的应用,能求出关于a的不等式-5<2a≤-4是解此题的关键.