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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 8: a 1/2-(2/3x-1/3)=2/3 b 3/x+5=15%

Home/ Toán Lớp 8: a 1/2-(2/3x-1/3)=2/3 b 3/x+5=15%

Toán Lớp 8: a 1/2-(2/3x-1/3)=2/3 b 3/x+5=15%

Tháng Mười Hai 11, 2022 Toán học 2 Comments 0 views

Toán Lớp 8: a 1/2-(2/3x-1/3)=2/3 b 3/x+5=15%

Comments ( 2 )

  1. lanhuongthu
    lanhuongthu
    11 Tháng Mười Hai, 2022 at 10:44 chiều
    Reply
    Lời giải :
    a)1/2-(2/3x-1/3)=2/3
    <=>1/2-2/3x+1/3=2/3
    <=>5/6-2/3x=2/3
    <=>-2/3x=2/3-5/6
    <=>-2/3x=-1/6
    <=>x=1/4
    Vậy x=1/4
    b)3/{x+5}=15%
    ĐK : x ne -5
    <=>3/{x+5}=3/20
    <=>3(x+5)=60
    <=>3x+15=60
    <=>3x=45
    <=>x=45(t//m)
    Vậy x=45

  2. quynhmaithu
    quynhmaithu
    11 Tháng Mười Hai, 2022 at 10:44 chiều
    Reply
    Bạn tham khảo:
    a. \frac{1}{2}-(\frac{2}{3}x-\frac{1}{3})=\frac{2}{3}.
    $⇔\dfrac{1}{2}-\dfrac{2x}{3}+\dfrac{1}{3}=\dfrac{2}{3}$.
    $⇔-\dfrac{2x}{3}+\dfrac{5}{6}=\dfrac{2}{3}$.
    $⇔-\dfrac{2x}{3}=-\dfrac{1}{6}$.
    $⇔-2x=-\dfrac{1}{2}$.
    $⇔x=\dfrac{1}{4}$.
    Vậy: $x=\dfrac{1}{4}$.
    b. $\dfrac{3}{x+5}=15\%$. (Điều kiện: $x \neq -5$).
    $⇔\dfrac{3}{x+5}=\dfrac{3}{20}$.
    $⇔\dfrac{60}{20(x+5)}=\dfrac{3(x+5)}{20(x+5)}$.
    $⇔60=3x+15$.
    $⇔-3x=-45$.
    $⇔x=15$.
    Vậy: $x=15$.

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222-9+11+12:2*14+14 = ? ( )

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