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