第一周　（代数初步知识能力训练）一、判断题（１６分）１．２ａ＝０是代数式．（　）２．ｘ２－４＝２１是方程．（　）３．方程６ｘ－２＝０的解是ｘ＝３．（　）４．（ｘ＋ｙ）２的意义是ｘ加ｙ的平方．（　）５．如果ａ２＋ｂ２＝０，那么ａ＝０，且ｂ＝０．（　）６．ａ The first week (algebraic initial knowledge ability training) 1. The judgment question (16 points) 1.2a = 0 is algebraic. () 2. X2-4=21 is the equation. () 3. The solution of equation 6x-2=0 is x=3. () 4. The meaning of (x+y)2 is x plus the square of y. () 5. If a2+b2=0, then a=0 and b=0. () 6. a