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18 tháng 2 2016

(1/3)^2-x-1=3^5

x=(1/3)^2x-1=243

x=(1/3)^2x=243-1

x=(1/3)^2x=242

x=1/9.x=242

x=242:1/9

x=26,88

16 tháng 8 2019

1a) \(\left|\frac{3}{2}x+\frac{1}{2}\right|=\left|4x-1\right|\)

=> \(\orbr{\begin{cases}\frac{3}{2}x+\frac{1}{2}=4x-1\\\frac{3}{2}x+\frac{1}{2}=1-4x\end{cases}}\)

=> \(\orbr{\begin{cases}-\frac{5}{2}x=-\frac{3}{2}\\\frac{11}{2}x=\frac{1}{2}\end{cases}}\)

=> \(\orbr{\begin{cases}x=\frac{5}{3}\\x=\frac{1}{11}\end{cases}}\)

b) \(\left|\frac{5}{4}x-\frac{7}{2}\right|-\left|\frac{5}{8}x+\frac{3}{5}\right|=0\)

=>\(\left|\frac{5}{4}x-\frac{7}{2}\right|=\left|\frac{5}{8}x+\frac{3}{5}\right|\)

=> \(\orbr{\begin{cases}\frac{5}{4}x-\frac{7}{2}=\frac{5}{8}x+\frac{3}{5}\\\frac{5}{4}x-\frac{7}{2}=-\frac{5}{8}x-\frac{3}{5}\end{cases}}\)

=> \(\orbr{\begin{cases}\frac{5}{8}x=\frac{41}{10}\\\frac{15}{8}x=\frac{29}{10}\end{cases}}\)

=> \(\orbr{\begin{cases}x=\frac{164}{25}\\x=\frac{116}{75}\end{cases}}\)

c) TT

16 tháng 8 2019

a, \(\left|\frac{3}{2}x+\frac{1}{2}\right|=\left|4x-1\right|\)

=> \(\orbr{\begin{cases}\frac{3}{2}x+\frac{1}{2}=4x-1\\-\frac{3}{2}x-\frac{1}{2}=4x-1\end{cases}}\)

=> \(\orbr{\begin{cases}\frac{3}{2}x+\frac{1}{2}-4x=-1\\-\frac{3}{2}x-\frac{1}{2}-4x=-1\end{cases}}\)

=> \(\orbr{\begin{cases}x=\frac{3}{5}\\x=\frac{1}{11}\end{cases}}\)

\(b,\left|\frac{5}{4}x-\frac{7}{2}\right|-\left|\frac{5}{8}x+\frac{3}{5}\right|=0\)

=> \(\left|\frac{5}{4}x-\frac{7}{2}\right|-0=\left|\frac{5}{8}x+\frac{3}{5}\right|\)

=> \(\frac{\left|5x-14\right|}{4}=\frac{\left|25x+24\right|}{40}\)

=> \(\frac{10(\left|5x-14\right|)}{40}=\frac{\left|25x+24\right|}{40}\)

=> \(\left|50x-140\right|=\left|25x+24\right|\)

=> \(\orbr{\begin{cases}50x-140=25x+24\\-50x+140=25x+24\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{164}{25}\\x=\frac{116}{75}\end{cases}}\)

c, \(\left|\frac{7}{5}x+\frac{2}{3}\right|=\left|\frac{4}{3}x-\frac{1}{4}\right|\)

=> \(\orbr{\begin{cases}\frac{7}{5}x+\frac{2}{3}=\frac{4}{3}x-\frac{1}{4}\\-\frac{7}{5}x-\frac{2}{3}=\frac{4}{3}x-\frac{1}{4}\end{cases}}\)

=> \(\orbr{\begin{cases}x=-\frac{55}{4}\\x=-\frac{25}{164}\end{cases}}\)

Bài 2 : a. |2x - 5| = x + 1

 TH1 : 2x - 5 = x + 1

    => 2x - 5 - x = 1

    => 2x - x - 5 = 1

    => 2x - x = 6

    => x = 6

TH2 : -2x + 5 = x + 1

   => -2x + 5 - x = 1

   => -2x - x + 5 = 1

   => -3x = -4

   => x = 4/3

Ba bài còn lại tương tự

13 tháng 10 2020

\(\text{a, }\frac{-2}{5}+x=\left(\frac{-1}{3}\right)^2+\frac{2}{3}\)

\(\Leftrightarrow\frac{-2}{5}+x=\frac{1}{9}+\frac{6}{9}\)

\(\Leftrightarrow\text{ }\frac{-2}{5}+x=\frac{7}{9}\)

\(\Leftrightarrow\text{ }x=\frac{7}{9}-\frac{-2}{5}\)

\(\Leftrightarrow\text{ }x=\frac{53}{45}\)

\(\text{Vậy }x=\frac{53}{45}\)

\(\text{Chia hay cộng mình không biết nên mình làm 2 TH, cái nào đúng đề thì bạn nhìn nha:}\)

\(\text{TH 1: Dấu chia}\)

\(\text{b, }\frac{3}{5}-2x=\left(\frac{-3}{5}\right)^2:\frac{9}{25}\)

\(\text{ }\Leftrightarrow\frac{3}{5}-2x=\frac{9}{25}:\frac{9}{25}\)

\(\text{ }\Leftrightarrow\frac{3}{5}-2x=1\)

\(\text{ }\Leftrightarrow2x=\frac{3}{5}-1\)

\(\text{ }\Leftrightarrow2x=\frac{3}{5}-1\)

\(\text{ }\Leftrightarrow2x=\frac{-2}{5}\)

\(\text{ }\Leftrightarrow x=\frac{-2}{5}:2\)

\(\text{ }\Leftrightarrow x=\frac{-1}{5}\)

\(\text{Vậy }\text{​​}x=\frac{-1}{5}\)

\(\text{TH 2:Dấu cộng}\)

\(\text{b, }\frac{3}{5}-2x=\left(\frac{-3}{5}\right)^2+\frac{9}{25}\)

\(\Leftrightarrow\frac{3}{5}-2x=\frac{9}{25}+\frac{9}{25}\)

\(\Leftrightarrow\frac{3}{5}-2x=\frac{18}{25}\)

\(\Leftrightarrow2x=\frac{3}{5}-\frac{18}{25}\)

\(\Leftrightarrow2x=\frac{-3}{25}\)

\(\Leftrightarrow x=\frac{-3}{25}:2\)

\(\Leftrightarrow x=\frac{-3}{50}\)

\(\text{Vậy }x=\frac{-3}{50}\)

\(\text{c, }\left|2x-1\right|=\frac{1}{2}-\frac{-2}{3}\)

\(\Leftrightarrow\left|2x-1\right|=\frac{7}{6}\)

\(\Leftrightarrow\left[{}\begin{matrix}2x-1=\frac{7}{6}\\2x-1=\frac{-7}{6}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=\frac{13}{6}\\2x=\frac{-1}{6}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\frac{13}{12}\\x=\frac{-1}{12}\end{matrix}\right.\)

\(\text{Vậy }x\in\left\{\frac{13}{12};\frac{-1}{12}\right\}\)

\(\text{d, }\left(x-\frac{3}{4}\right).\frac{1}{2}=\left(\frac{-1}{2}\right)^2\)

\(\Leftrightarrow\left(x-\frac{3}{4}\right).\frac{1}{2}=\frac{1}{4}\)

\(\Leftrightarrow x-\frac{3}{4}=\frac{1}{4}:\frac{1}{2}\)

\(\Leftrightarrow x-\frac{3}{4}=\frac{1}{2}\)

\(\Leftrightarrow x=\frac{1}{2}+\frac{3}{4}\)

\(\Leftrightarrow x=\frac{5}{4}\)

\(\text{Vậy }x=\frac{5}{4}\)

22 tháng 6 2016

bạn coi lại đề

22 tháng 6 2016

ai giup tra loi voi