tính hợp lí A)(-87).(1-135)-135.87 B)(-45).(1+432)-432.(-45) C)63.(64-62)+62.(62-64) D)37.(25+27)-27.(37+25) E)5.(13-26)-26.

1 bình luận về “tính hợp lí A)(-87).(1-135)-135.87 B)(-45).(1+432)-432.(-45) C)63.(64-62)+62.(62-64) D)37.(25+27)-27.(37+25) E)5.(13-26)-26.”

1.  A) (-87)(1-135)-135.87
   = 87(-1+135-135)
   = 87(-1)
   = -87
   B) (-45)(1+432)-432(-45)
   = -45(1+432-432)
   = -45.1
   = -45
   C) 63(64-62)+62(62-64)
   = 63 (64-62)-62(64-62)
   = (63-62)(64-62)
   = 1.2
   = 2
   D) 37(25+27)-27(37+25)
   = 37.25 + 37.27 – 27.37 – 27.25
   = (37.25-27.25) + (37.27 – 27.37)
   = 25(37-27) + 0
   = 25.10
   = 250
   E) 5(13-26)-26(13-5)+21.13
   = 5.13-5.26 -26.13+26.5+21.13
   =(26.5-5.26) + (5.13+21.13) -26.13
   = 0 + 13(5+21) -26.13
   =13.26-26.13
   =0

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