Tìm x, biết………………………

Question

Tìm x, biết………………………
tim-biet

in progress 0
Gerda 4 years 2020-11-10T12:52:28+00:00 1 Answers 65 views 0

Answers ( )

  1. Maris
    0
    2020-11-10T12:54:21+00:00
    Reply

    Đáp án:

    \[x = \dfrac{{91}}{{16}}\]

    Giải thích các bước giải:

     Ta có:

    \(\begin{array}{l}
    \dfrac{2}{5} – \dfrac{3}{5}.\left( {x – 2} \right) = {\left( {\dfrac{{ – 1}}{2}} \right)^3} – {\left( {\dfrac{3}{4}} \right)^3}.{\left( { – 2} \right)^2}\\
     \Leftrightarrow \dfrac{2}{5} – \dfrac{3}{5}.\left( {x – 2} \right) = \dfrac{{ – 1}}{8} – {\left( {\dfrac{3}{4}} \right)^3}.4\\
     \Leftrightarrow \dfrac{2}{5} – \dfrac{3}{5}.\left( {x – 2} \right) =  – \dfrac{1}{8} – \dfrac{{{3^3}}}{{{4^2}}}\\
     \Leftrightarrow \dfrac{2}{5} – \dfrac{3}{5}\left( {x – 2} \right) =  – \dfrac{1}{8} – \dfrac{{27}}{{16}}\\
     \Leftrightarrow \dfrac{2}{5} – \dfrac{3}{5}\left( {x – 2} \right) =  – \dfrac{{29}}{{16}}\\
     \Leftrightarrow \dfrac{3}{5}.\left( {x – 2} \right) = \dfrac{2}{5} – \left( { – \dfrac{{29}}{{16}}} \right)\\
     \Leftrightarrow \dfrac{3}{5}\left( {x – 2} \right) = \dfrac{{177}}{{80}}\\
     \Leftrightarrow x – 2 = \dfrac{{177}}{{80}}:\dfrac{3}{5}\\
     \Leftrightarrow x – 2 = \dfrac{{59}}{{16}}\\
     \Leftrightarrow x = \dfrac{{59}}{{16}} + 2\\
     \Leftrightarrow x = \dfrac{{91}}{{16}}
    \end{array}\)

    Vậy \(x = \dfrac{{91}}{{16}}\)

Leave an answer

Browse

Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )