Question

[Pham thi thu Phuong]

1, Rút gọn

 1.3.5.7...4926.27.....50" role="presentation" style="border:0px; box-sizing:border-box; direction:ltr; display:inline-table; font-size:18px; font-style:normal; font-weight:normal; letter-spacing:normal; line-height:normal; margin:0px; max-height:none; max-width:none; min-height:0px; min-width:0px; padding:0px; position:relative; text-align:left; text-indent:0px; text-transform:none; white-space:nowrap; word-spacing:normal; word-wrap:normal" class="MathJax">1.3.5.7...4926.27.....50