Question

已知集合A{1,3,a},若3a-2属于A,求实数a的取值集合

Answer 1

若3a-2=1,则a=1.但a^2也为1,不满足；若3a-2=3,a=5/3,满足；若3a-2=a^2,a^2-3a+2=0,a=1或2,同样,当a=1时,a^2=1,不满足,故a只能为2.综上所述,a的取值集合为：{5/3,2}