Tính 7.9-14 / 3-17 25%-3/2+0,5.12/5.25%-1 Tìm x ( 14/5x + 50 ) :2/3 = -51 8x-0,4 = 7,8x + 402 Giúp mik hết nha r Mik sẽ vote + CTLHN

Question

Tính
7.9-14 / 3-17
25%-3/2+0,5.12/5.25%-1
Tìm x
( 14/5x + 50 ) :2/3 = -51
8x-0,4 = 7,8x + 402
Giúp mik hết nha r Mik sẽ vote + CTLHN

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Madeline 1 năm 2021-09-23T15:45:44+00:00 2 Answers 4 views 0

Answers ( )

    0
    2021-09-23T15:46:54+00:00

    7.9- 14/3- 17

    =7.9-(7.2)tất cả trên 3-17

    =7.(9-2) tất cả trên 3-17

    =7.7 tất cả trên 3-17

    =-49/51

    25%- 3/2 + 0,5. 12/5. 25%- 1

    =1/4 – 3/2 + 1/2.12/5. 1/4- 1

    =1/4 – 3/2 + 6/5.1/4-1

    =1/4 – 3/2 + 3/10-1

    =5/20 – 30/20 + 6/20 – 20/20

    = -25/20 -14/20

    = -39/20

    (14/5x + 50): 2/3= -51

    14/5x + 50= -51. 2/3

    14/5x + 50= -102/3

    14/5x= -102/3-50

    14/5x= -102/3- 150/3

    14/5x= -252/3

    x= -252/3: 14/5

    x= -252/3. 5/14

    x= -30              Vậy x=-30

    8x-04= 7,8 +402

    8x-2/5= 39/5 +402

    8x-39/5= 2/5+ 402

    x.(8-39/5)= 2/5+ 2010/5

    x.(40/5-39/5)= 2012/5

    x.1/5= 2012/5

    x= 2012/5:1/5

    x= 2012/5. 5

    x= 2012

            Nhớ vote mình 5???? nhé!

    0
    2021-09-23T15:47:14+00:00

    Đáp án:

     

    Giải thích các bước giải:

    7.9-14 / 3-17

    $=\frac{7. 9- 7.2}{-14}$

    $= \frac{7. (9- 2)}{-14}$

    $= \frac{7. 7}{-14}$

    $= \frac{49}{-14}$

    $= \frac{-7}{2}$ (đổi dấu)

    `25\%-3/2+0,5.12/5.2\5%-1`

    $= \frac{1}{4}- \frac{3}{2}+ \frac{1}{2}. \frac{12}{5}. \frac{1}{4}- 1$

    $= \frac{1}{4}- \frac{3}{2}+ \frac{3}{10}- 1$

    $= \frac{5}{20}- \frac{30}{20}+ \frac{6}{20}$

    $= \frac{5- 30+ 6}{20}= \frac{-21}{20}$

    Tìm `x`

    `( 14/5x + 50 ) :2/3 = -51`

     $\frac{14}{5}x+ 50= -51. \frac{2}{3}$

     $\frac{14}{5}x+ 50= -34$

    $\frac{14}{5}x = -34- 50$

    $\frac{14}{5}x= -84$

    $x= -84: \frac{14}{5}$

    $x= -30$

    `8x-0,4 = 7,8x + 402`

    $8x- 7,8. x= 402+ 0,4$

    $0, 2. x= 402,04$

    $x= 402,04: 2$

    $x= 2012$

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