a)3/4-4/5+-17/20 b)-6/8.24/18-5/9 c)(-12/5+5/12+1/4)+(7/5+-19/12+2/12)-2019^0 d)2/5.(-5/12+-9/13)-2/5.(4/13-5/12):2

0 bình luận về “a)3/4-4/5+-17/20 b)-6/8.24/18-5/9 c)(-12/5+5/12+1/4)+(7/5+-19/12+2/12)-2019^0 d)2/5.(-5/12+-9/13)-2/5.(4/13-5/12):2”

1. Đáp án:

    

   Giải thích các bước giải:

    ` 3/4 – 4/5 + -17/20 `

   ` 15/20 + ( – 16/20 ) + – 17/20 `

   ` – 1/20 + – 17/20 `

   `-9/10 `

   ` b)-6/(8).(24)/18-5/9 `

   ` = -1 – 5/9 `

   ` = -14/9 ` 

   ` c)(-12/5+5/12+1/4)+(7/5+(-19)/12+2/12)-2019^0 ` 

   ` = (-12/5+5/12+1/4)+(7/5+-19/12+2/12) – 1 `

   ` = – 26/15 + -1/60 – 1 `

   ` = -11/4 `

   ` d)2/5.(-5/12+(-9)/13)-2/5.(4/13-5/12):2 ` 

   ` = 2/5 . -173/156 – 2/5 . 11/12 : 2 `

   ` = 2/5 . ( 173/156 – 11/12 : 2 ) `

   ` = 2/5 . 5/52 `

   ` = 1/26 `

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2. a) 3/4 – 4/5 + (-17/20)

   = 3/4 – 4/5 – 17/20

   = 15/20 – 16/20 – 17/20 

   = -9/10 

   b) -6/8 . 24/18 – 5/9 

   = -1 – 5/9 = -14/9 

   c) ( -12/5 + 5/12 + 1/4 ) + [(7/5 + ( -19/12) + 2/12 ] – 2019^0

    = -12/5 + 5/12 + 1/4 + 7/5 – 19/12 + 2/12 – 1 

   = ( -12/5 + 7/5 ) + ( 5/12 – 19/12 + 2/12 ) + 1/4 – 1

   = -1 -1 + 1/4 -1 

   = -3 + 1/4 = – 11/4 

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