题目内容
(2013?南雄市)若实数a满足a2-2a-1003=0,则2a2-4a+5=
2011
2011
.分析:先根据等式的性质把a2-2a-1003=0的两边同时乘2,得出2a2-4a-2006=0,进而可得2a2-4a=2006,然后代入2a2-4a+5解答即可.
解答:解:a2-2a-1003=0
2a2-4a-2006=0
2a2-4a=2006
2a2-4a+5
=2006+5
=2011
故答案为:2011.
2a2-4a-2006=0
2a2-4a=2006
2a2-4a+5
=2006+5
=2011
故答案为:2011.
点评:本题关键是把“a2-2a”看作一个整体,先求出a2-2a的值,再代入要求的式子即可.
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