Tìm x biết ​(x in BCleft( {26;39;260} right),2000

 (begin{array}{l} 26 = 2.13\ 39 = 3.13\ 260 = {2^2}.5.13\ Rightarrow BCNNleft( {26;39;260} right) = {2^2}.3.5.13 = 780\ Rightarrow BCleft( {26;39;260} right) = Bleft( {780} right) = left{ {0;780;1560;2340;3120;…} right}\ ma,,2000 < x < 3000 Rightarrow x = 2340 end{array} )