20 0 3年天津市中考试卷第 18题 (填空 )是这样的 :如果a、b、c为互不相等的实数 ,且满足关系式b2 +c2 =2a2 +16a+14与bc=a2 -4a -5 ,那么a的取值范围是.本题原创性强 ,解题思路灵活 ,因而被不少资料引用 ,但据试卷提供的评分标准和相关引用资料配备的参考答案 ,都认为a的取值 The 20th year of the Tianjin Intermediate School Examination Paper No. 18 (fill in blank) is such that if a, b, and c are unequal real numbers, and the relations b2 + c2 = 2a2 + 16a + 14 and bc = a2 - 4a are satisfied -5, then a’s range of values ​​is. The originality of the problem is strong, and the problem-solving idea is flexible, so it is cited by a lot of data, but according to the scoring standards provided by the test paper and the reference answers provided by relevant citations, the value of a is considered