Đề bài

Điền các dấu \(\left( { \in , \notin } \right)\) thích hợp vào ô vuông: \(\eqalign{  & 5\,...\,Z\,;\,\,\,\,\,\,\,\,\,\,\,\, - 2\,...\,Q;\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\sqrt 2 \,...\,Q  \cr  & {3 \over 5}\,...\,Q\,;\,\,\,\,\,\,\,\,\, - {3 \over 5}\,\,...\,I \cr} \) \(\eqalign{  & 2,31(45)\,\,...\,\,I\,;\,\,\,\,\,\,\,\,\,\,\,\, - 3,45(63)\,\,...\,I  \cr  & 7,62(38)\,...\,R\,;\,\,\,\,\,\,\,\,\,\,\,\,\,0\,...\,I \cr} \)

Lời giải chi tiết

\(\eqalign{  & 5 \in Z; - 2 \in Q;\sqrt 2  \notin Q;{3 \over 5} \in Q; - {3 \over 5} \notin I  \cr  & 2,31(45) \notin I; - 3,45(63) \notin I;7,62(38) \in R;0 \notin I \cr} \)

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