a) 3/5 + ( -4/3) + ( -3/4) b) X – 2/7=7/21 c) 11/12 – ( 2/5+ X ) = 2/3 d) 3/7 – X = 1/4 – ( – 3/5 ) e) 3/35 – ( 3/5 + X ) = 2/7 f) 2/9 – (1/3- X )

a) 3/5 + ( -4/3) + ( -3/4)
b) X – 2/7=7/21
c) 11/12 – ( 2/5+ X ) = 2/3
d) 3/7 – X = 1/4 – ( – 3/5 )
e) 3/35 – ( 3/5 + X ) = 2/7
f) 2/9 – (1/3- X ) = 5/6
g) 4 1/5 : (-2 4/5)
nếu câu nào dài quá thì ghi mỗi kết quả phép tính cũng đc

0 bình luận về “a) 3/5 + ( -4/3) + ( -3/4) b) X – 2/7=7/21 c) 11/12 – ( 2/5+ X ) = 2/3 d) 3/7 – X = 1/4 – ( – 3/5 ) e) 3/35 – ( 3/5 + X ) = 2/7 f) 2/9 – (1/3- X )”

  1. `a) 3/5 + (-4)/3 + (-3)/4`

    `= 36/60 – 80/60 – 45/60`

    ` = -89/60`

    `b) x – 2/7 = 7/21`

    `=> x – 2/7 = 1/3`

    `=> x = 1/3 + 2/7`

    `=> x = 13/21`

    Vậy `x=13/21`

    `c) 11/12 – (2/5 + x)  =2/3`

    `=> 2/5 + x = 11/12 – 2/3`

    `=> 2/5 + x = 1/4`

    `=> x = 1/4 – 2/5`

    `=> x = -3/20`

    Vậy `x=-3/20`

    `d) 3/7  – x = 1/4 – (-3/5)`

    `=> 3/7- x = 17/20`

    `=> x = 3/7  – 17/20`

    `=>x = -59/140`

    Vậy `x = -59/140`

    `e) 3/35 – (3/5 + x) = 2/7`

    `=> 3/5 + x = 3/35 – 2/7`

    `=> 3/5 + x = -1/5`

    `=> x = -1/5 – 3/5`

    `=> x = -4/5`

    Vậy `x=-4/5`

    `f) 2/9 – (1/3 – x) = 5/6`

    `=> 1/3 – x= 2/9 – 5/6`

    `=> 1/3 – x = -11/18`

    `=> x = 1/3+ 11/18`

    `=> x = 17/18`

    Vậy `x=17/18`

    `g) 4 1/5 : (-2 4/5)`

    ` = 21/5 : (-14)/5`

    ` = 21/5 . (-5)/14`

    ` = -3/2`

     

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  2. `a)3/5+(-4/3)+(-3/4)`

    `=36/60+(-80/60)+(-45/60)`

    `=(36-80-45)/(60)`

    `=-89/60`

    `b)x-2/7=7/(21)`

       `x-2/7=1/3`

       `x=1/3+2/7`

       `x=7/(21)+6/(21)`

       `x=13/21` 

    Vậy `x=13/21`

    `c)11/12-(2/5+x)=2/3`

                  `2/5+x=11/12 – 2/3`

                  `2/5+x=11/12-8/(12)`

                  `2/5+x=3/(12)`

                  `2/5 +x=1/4`

                           `x=1/4 – 2/5`

                           `x=5/(20)-8/(20)`

                           `x=-3/(20)`

    Vậy `x=-3/(20)`

    `d)3/7-x=1/4-(-3/5)`

       `3/7-x=1/4+3/5`

       `3/7-x=5/(20)+12/20`

       `3/7-x=17/20`

              `x=3/7 – 17/20`

              `x=(-59)/(140)`

    Vậy `x=(-59)/(140)`

    `e)3/(35)-(3/5+x)=2/7`

                  `3/5+x=3/(35) – 2/7`

                  `3/5 + x=-1/5`

                           `x=-1/5 – 3/5`

                           `x=-4/5`

                  Vậy `x=-4/5`

    `f)2/9 – (1/3-x)=5/6`

               `1/3-x=2/9-5/6`

               `1/3-x=-11/18`

                      `x=1/3-(-11/18)`

                      `x=1/3+11/18`

                      `x=17/18`

              Vậy `x=17/18`

    `g) 4 1/5 : (-2 4/5)`

    `=(21)/5 : (-14/5)`

    `=(21)/5 . (-5/14)`

    `=-3/2` 

     

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