Bạn ơi, bạn viết lại đề đi. Khó nhìn quá

ok bạn 

Bài 1 :

\(-\frac{1}{2}-\left|\frac{3}{7}-x\right|=0,75\)

\(\left|\frac{3}{7}-x\right|=-\frac{1}{2}-0,75\)

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

Vì x > 0

=> Không tõa mãn điều kiện

Bài 2 :

\(\frac{4}{5}+\frac{3}{2}.\left|x+\frac{1}{4}\right|=\frac{1}{2}\)

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

\(\frac{3}{2}.\left|x+\frac{1}{4}\right|=-\frac{3}{10}\)

\(\left|x+\frac{1}{4}\right|=-\frac{3}{10}:\frac{3}{2}\)

\(\left|x+\frac{1}{4}\right|=-\frac{3}{10}.\frac{2}{3}\)

\(\left|x+\frac{1}{4}\right|=-\frac{1}{5}\)

Vì x > 0 

Vậy không thõa mãn điều kiện

tui giải kiểu lop7 

bài1: bỏ tgtđ thì +- nhé

-1/2 -3/7+x =0,75

x= 47/28

-1/2+3/7-x = 0,75

x= -23/28

\(\Leftrightarrow\left(\dfrac{-3}{4}x+\dfrac{5}{2}\right)\cdot\dfrac{4}{7}=\dfrac{-5}{6}-\dfrac{1}{3}=\dfrac{-4}{3}\)

\(\Leftrightarrow-\dfrac{3}{4}x+\dfrac{5}{2}=\dfrac{-4}{3}:\dfrac{4}{7}=\dfrac{-7}{3}\)

=>-3/4x=-29/6

hay x=58/9

`(-0,75.x+5/2). 4/7-(-1/3)=[-5]/6`

`(-3/4 .x+5/2). 4/7=-7/6`

`-3/4 .x+5/2=-49/24`

`-3/4 .x=-109/24`

`x=109/18`

\(a)\) \(\left|x\right|=\left|x+2\right|=3\)

\(\text{Trường hợp 1:}\)

\(\Leftrightarrow x+x+2=3\)

\(\Leftrightarrow2x=1\)

\(\Leftrightarrow x=\frac{1}{2}\)

\(\text{Trường hợp 2:}\)

\(\Leftrightarrow-x-x-2=3\)

\(\Leftrightarrow-2x=5\)

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

\(b)\) \([\frac{12}{25}.\left(0,75+\frac{7}{4}\right)-1].x=[\frac{7}{5}-\frac{3}{25}.\left(10,6-\frac{3}{5}\right)]\)

\(\Leftrightarrow[\frac{12}{25}.2,5-1].x=[\frac{7}{5}-\frac{3}{25}.10]\)

\(\Leftrightarrow[1,2-1].x=[\frac{7}{5}-2]\)

\(\Leftrightarrow0,2.x=-\frac{3}{5}\)

\(\Leftrightarrow x=-\frac{3}{5}:0,2\)

\(\Leftrightarrow x-3\)

a: \(\Leftrightarrow x\cdot\dfrac{3}{5}=\dfrac{-1}{7}+\dfrac{1}{2}=\dfrac{1}{2}-\dfrac{1}{7}=\dfrac{5}{14}\)

\(\Leftrightarrow x=\dfrac{5}{14}:\dfrac{3}{5}=\dfrac{25}{42}\)

b: =>|3x-1|=2

\(\Leftrightarrow\left[{}\begin{matrix}3x-1=2\\3x-1=-2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\\x=-\dfrac{1}{3}\end{matrix}\right.\)

c: \(\Leftrightarrow7\left(37-x\right)=3\left(x-13\right)\)

=>259-7x=3x-39

=>-10x=-298

hay x=29,8

d: =>x=3/4+2/3=9/12+8/12=17/12

a: \(B=\frac12-\left\lbrack\frac38+\left(-\frac74\right)\right\rbrack\)

\(=\frac12-\frac38+\frac74\)

\(=\frac48-\frac38+\frac{14}{8}=\frac{15}{8}\)

b: \(-\frac{4}{12}-\left(-\frac{13}{39}-0,25\right)+0,75\)

\(=-\frac13+\frac13+0,25+0,75\)

=0,25+0,75

=1

c: \(\frac12-\frac13+\frac{1}{23}+\frac16\)

\(=\left(\frac12-\frac13+\frac16\right)+\frac{1}{23}\)

\(=\left(\frac16+\frac16\right)+\frac{1}{23}=\frac13+\frac{1}{23}=\frac{26}{69}\)

d: \(\left(-\frac{13}{7}-\frac49\right)-\left(-\frac{10}{7}-\frac49\right)\)

\(=-\frac{13}{7}-\frac49+\frac{10}{7}+\frac49\)

\(=-\frac{13}{7}+\frac{10}{7}=-\frac37\)

e: \(\left(\frac78-\frac52+\frac47\right)-\left(-\frac37+1-\frac{13}{8}\right)\)

\(=\frac78-\frac52+\frac47+\frac37-1+\frac{13}{8}\)

\(=\frac{20}{8}-\frac52=0\)

f: \(-\frac37+\left(3-\frac34\right)-\left(2,25-\frac{10}{7}\right)\)

\(=-\frac37+3-\frac34-2,25+\frac{10}{7}\)

\(=\frac77+0,75-\frac34\)

=1
g: \(\left(\frac53-\frac37+9\right)-\left(2+\frac57-\frac23\right)+\left(\frac87-\frac43-10\right)\)

\(=\frac53-\frac37+9-2-\frac57+\frac23+\frac87-\frac43-10\)

\(=\left(\frac53+\frac23-\frac43\right)+\left(-\frac37-\frac57+\frac87\right)+\left(9-2-10\right)\)

\(=\frac33+7-10=1-3=-2\)