1,x:1,75=1 3/10+45% 2,5-x/12+5/12-1/8=3/8 3,|x-25/35|-3/11=2/3

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1. Đáp án:

   $\begin{array}{l}
   1)x:1,75 = 1\frac{3}{{10}} + 45\% \\
    \Rightarrow x:\frac{{175}}{{100}} = \frac{{13}}{{10}} + \frac{{45}}{{100}}\\
    \Rightarrow x:\frac{{175}}{{100}} = \frac{{13}}{{10}} + \frac{9}{{20}}\\
    \Rightarrow x:\frac{7}{4} = \frac{{26 + 9}}{{20}} = \frac{{35}}{{20}}\\
    \Rightarrow x = \frac{{35}}{{20}}.\frac{7}{4} = \frac{{49}}{{16}}\\
   2)\frac{{5 – x}}{{12}} + \frac{5}{{12}} – \frac{1}{8} = \frac{3}{8}\\
    \Rightarrow \frac{{5 – x + 5}}{{12}} = \frac{3}{8} + \frac{1}{8} = \frac{1}{2}\\
    \Rightarrow \frac{{10 – x}}{{12}} = \frac{1}{2} = \frac{6}{{12}}\\
    \Rightarrow 10 – x = 6\\
    \Rightarrow x = 10 – 6 = 4\\
   Vay\,x = 4\\
   3)\left| {x – \frac{{25}}{{35}}} \right| – \frac{3}{{11}} = \frac{2}{3}\\
    \Rightarrow \left| {x – \frac{5}{7}} \right| = \frac{2}{3} + \frac{3}{{11}} = \frac{{22 + 9}}{{33}} = \frac{{31}}{{33}}\\
    \Rightarrow \left[ \begin{array}{l}
   x – \frac{5}{7} = \frac{{31}}{{33}}\\
   x – \frac{5}{7} =  – \frac{{31}}{{33}}
   \end{array} \right.\\
    \Rightarrow \left[ \begin{array}{l}
   x = \frac{{31}}{{33}} + \frac{5}{7} = \frac{{31.7 + 5.33}}{{33.7}} = \frac{{382}}{{231}}\\
   x = \frac{{ – 31}}{{33}} + \frac{5}{7} = \frac{{ – 52}}{{231}}
   \end{array} \right.
   \end{array}$

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