Tìm x a) 3/2 – ( x- 7/3)= giá trị tuyệt đối của -3/4 – 9/8 b) 5/2 – ( 3/2-7/3+x)= 8/15- ( 1/4-7/10) c) 3( 1/2-x ) +1/3= 7/6-x d) 1/2 ( x-3)+2/7 * ( 7

Tìm x
a) 3/2 – ( x- 7/3)= giá trị tuyệt đối của -3/4 – 9/8
b) 5/2 – ( 3/2-7/3+x)= 8/15- ( 1/4-7/10)
c) 3( 1/2-x ) +1/3= 7/6-x
d) 1/2 ( x-3)+2/7 * ( 7x-4) = 10

0 bình luận về “Tìm x a) 3/2 – ( x- 7/3)= giá trị tuyệt đối của -3/4 – 9/8 b) 5/2 – ( 3/2-7/3+x)= 8/15- ( 1/4-7/10) c) 3( 1/2-x ) +1/3= 7/6-x d) 1/2 ( x-3)+2/7 * ( 7”

  1. $a$) `3/2 – (x – 7/3) = |-3/4 – 9/8|`

    `⇔ 3/2 – (x – 7/3 ) = 15/8`

    `⇔ x – 7/3 =-3/8`

    `⇔ x = 47/24`

      Vậy `x=47/24`

    $b$) `5/2 – (3/2 – 7/3  + x) = 8/15 – (1/4 – 7/10)`

    `⇔ 5/2 – 3/2 + 7/3 – x = 8/15 – 1/4 + 7/10`

    `⇔ 1 + 7/3 – x = 59/60`

    `⇔ x = 47/20`

       Vậy `x=47/20`

    $c$) `3(1/2 – x) + 1/3 = 7/6 – x`

    `⇔ 3/2 – 3x + 1/3 = 7/6 – x`

    `⇔ -2x = 7/6 – 1/3 – 3/2`

    `⇔ -2x = -2/3`

    `⇔ x = 1/3`

      Vậy `x=1/3`

    $d$) `1/2 (x-3) + 2/7 . (7x -4) = 10`

    `⇔ 1/2 . x – 3/2 + 2x – 8/7 = 10`

    `⇔ 5/2 . x = 177/14`

    `⇔ x = 177/35`

     Vậy `x=177/35`

     

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  2. a) $\dfrac{3}{2}-(x-\dfrac{7}{3})=|-\dfrac{3}{4}-\dfrac{9}{8}|$

    $\dfrac{3}{2}-(x-\dfrac{7}{3})=\dfrac{15}{8}$

    $x-\dfrac{7}{3}=\dfrac{3}{2}-\dfrac{15}{8}$

    $x-\dfrac{7}{3}=-\dfrac{3}{8}$

    $⇒x=-\dfrac{3}{8}+\dfrac{7}{3}=\dfrac{47}{24}$

    b) $\dfrac{5}{2}-(\dfrac{3}{2}-\dfrac{7}{3}+x)=\dfrac{8}{15}-(\dfrac{1}{4}-\dfrac{7}{10})$

    $\dfrac{5}{2}-(-\dfrac{5}{6}+x)=\dfrac{8}{15}+\dfrac{9}{20}=\dfrac{59}{60}$

    $-\dfrac{5}{6}+x=\dfrac{5}{2}-\dfrac{59}{60}=\dfrac{91}{60}$

    $x=\dfrac{91}{60}+\dfrac{5}{6}=\dfrac{47}{20}$

    $⇒x=\dfrac{59}{60}-\dfrac{10}{3}=-\dfrac{47}{20}$

    c) $3.(\dfrac{1}{2}-x)+\dfrac{1}{3}=\dfrac{7}{6}-x$

    $\dfrac{3}{2}-3x+\dfrac{1}{3}-\dfrac{7}{6}+x=0$

    $(\dfrac{3}{2}-\dfrac{7}{6}+\dfrac{1}{3})+(-3x+x)=0$

    $\dfrac{2}{3}-2x=0$

    $2x=\dfrac{2}{3}$

    $⇒x=\dfrac{2}{3}:2=\dfrac{1}{3}$

    d) $\dfrac{1}{2}(x-3)+\dfrac{2}{7}.(7x-4)=10$

    $\dfrac{1}{2}x-\dfrac{3}{2}+2x-\dfrac{8}{7}=10$

    $(\dfrac{1}{2}x+2x)+(-\dfrac{3}{2}-\dfrac{8}{7})=10$

    $\dfrac{5}{2}x-\dfrac{37}{14}=10$

    $\dfrac{5}{2}x=10+\dfrac{37}{14}=\dfrac{177}{14}$

    $x=\dfrac{177}{14}:\dfrac{5}{2}=\dfrac{177}{35}$

     

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