... 102 43 425−+.A= 20 36 120486125202).2 43( 5.25−=−=−+(0,5®iÓm )b)B =20. 63. 26.2948810945+− = )5.2.( )3. 2 (3. 2 )3. 2.(2 )3. ()2(2881094252+−= )51 (3. 2) 13. (3. 25 .32 3.2 32 3.2810 39 108108109101210+−=+−= ... ®iÓm)−=++==⇒−===== .31 871285 31 812758,zyxzyyxzyxzyyxDoa−=++==⇒ .31 814242415zyxzyyx(0,5®iÓm)1 1 1 1 1 1 1) 3 18 54 108 180 270 37 81 1 1 1 1 1 1 1 1 1 1 1 1 1 3 3 3 6 6 9 9 12 12 15 15 18 18 211 1 1 1 1 2 5 3 3 3 21 3 21 21c C = ... AB.*********************Hết********************** đáp án Đề thi học sinh giỏi cấp huyện1 1 1 1 1 1 1) 3 8 54 108 180 270 37 8c C = M«n : To¸n –Líp : 7(thêi gian lµm bµi :120')C©u 1(2 ®iÓm) : Thùc hiÖn phÐp tÝnh:a, A = 33 2) 3 2(:)45(:25681.625)411.(0625,01−+.A...