问题
选择题
方程x2+|x|-1=0所有实数根的和等于( )
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答案
①当x≥0时;原方程可化为,x2+x-1=0,方程的根为:x=
;
-15 2
②当x<0时;原方程可化为,x2-x-1=0,方程的根为:x=
;-
+15 2
∴所有实数根的和
+
-15 2
=0-
+15 2
故选C.
方程x2+|x|-1=0所有实数根的和等于( )
|
①当x≥0时;原方程可化为,x2+x-1=0,方程的根为:x=
;
-15 2
②当x<0时;原方程可化为,x2-x-1=0,方程的根为:x=
;-
+15 2
∴所有实数根的和
+
-15 2
=0-
+15 2
故选C.
从对话后的选项中选择适当的选项补全对话。 | |
Susan and Harry arrive in a Tai restaurant. Somsak: The owner, comes out to greet them. Somsak: Ah! Miss Stewart! 1_______ How are you? Susan: Fine, Somsak. And you? Somsak: Fine, thank you. Susan: 2_______ Harry: Pleased to meet you, Somsak: 3_______ Any friend of Miss Stewart's is welcome. Somsak: Follow me, please. Harry: [to Susan] I like it here. Susan: 4_______ I come here often. Somsak: A special place for special people. Susan: Thank you. Somsak.
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