a, A = ( – 65 ) + ( – 64 ) + ( – 63 ) + … + 64 + 65 + 66 b, B = -2 + 4 + 6 – 8 – 10 + 12 + 14 – 16 – … – 90 + 92 + 94 – 9

1 bình luận về “a, A = ( – 65 ) + ( – 64 ) + ( – 63 ) + … + 64 + 65 + 66 b, B = -2 + 4 + 6 – 8 – 10 + 12 + 14 – 16 – … – 90 + 92 + 94 – 9”

1. A=[(-65)+65]+[(-64)+64]+[(-63)+63]

   A=0

   B=-2+4+6-8-10+12+14-16-…-90+92+94-96

   B=[(-2)+4+6-8]+[(-10)+12+14-16]+…+[(-90)+92+94-96]

   B=0+0+…+0

   B=0

   C=100-99-98+97+96-95-94+93+…+4-3-2+1

   C=(100-99-98+97)+(96-95-94+93)+…+(4-3-2+1)

   C=0+0+…+0

   C=0

    

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