1/5单选题
难度：
1.下列二次根式：①
；②2
；③
；④
，是最简二次根式的有（ ）
；②2；③；④，是最简二次根式的有（ ） | A | ①②④ |
| B | ②③④ |
| C | ①② |
| D | ②④ |
正确答案：RA==
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
，②
，③
，④
(x＞0)中，最简二次根式有（ ）个 
，以下说法不正确的是（ ）
，②
，③
。化简正确的有（）个。