2)≤ X ≤23(13−1

2 ) - DE DAP AN THI HSG TOAN 67 8 HUYEN THANH OAI
Lớp 6 Toán DE DAP AN THI HSG TOAN 67 8 HUYEN THANH OAI
2

)

≤ x ≤23

(

13−1