Bài 1: 

a) Ta có: \(\dfrac{17}{6}-x\left(x-\dfrac{7}{6}\right)=\dfrac{7}{4}\)

\(\Leftrightarrow\dfrac{17}{6}-x^2+\dfrac{7}{6}x-\dfrac{7}{4}=0\)

\(\Leftrightarrow-x^2+\dfrac{7}{6}x+\dfrac{13}{12}=0\)

\(\Leftrightarrow-12x^2+14x+13=0\)

\(\Delta=14^2-4\cdot\left(-12\right)\cdot13=196+624=820\)

Vì Δ>0 nên phương trình có hai nghiệm phân biệt là:

\(\left\{{}\begin{matrix}x_1=\dfrac{14-2\sqrt{205}}{-24}=\dfrac{-7+\sqrt{205}}{12}\\x_2=\dfrac{14+2\sqrt{2015}}{-24}=\dfrac{-7-\sqrt{205}}{12}\end{matrix}\right.\)

b) Ta có: \(\dfrac{3}{35}-\left(\dfrac{3}{5}-x\right)=\dfrac{2}{7}\)

\(\Leftrightarrow\dfrac{3}{5}-x=\dfrac{3}{35}-\dfrac{10}{35}=\dfrac{-7}{35}=\dfrac{-1}{5}\)

hay \(x=\dfrac{3}{5}-\dfrac{-1}{5}=\dfrac{3}{5}+\dfrac{1}{5}=\dfrac{4}{5}\)

ai giúp mik vs

Bài 3: 

a) Ta có: \(2x-3=x+\dfrac{1}{2}\)

\(\Leftrightarrow2x-x=\dfrac{1}{2}+3\)

\(\Leftrightarrow x=\dfrac{7}{2}\)

b) Ta có: \(4x-\left(x+\dfrac{1}{2}\right)=2x-\left(\dfrac{1}{2}-5\right)\)

\(\Leftrightarrow3x-\dfrac{1}{2}-2x+\dfrac{1}{2}-5=0\)

\(\Leftrightarrow x=5\)

a: =>x=3/7+3/5=15/35+21/35=36/35

b: =>x/35=4/5-5/7=28/35-25/35=3/35

=>x=3

c: =>x<3/4+8/4=11/4

=>\(x\in\left\{0;1;2;3\right\}\)

d: =>5/3<x<5/6+24/6=29/6

=>\(x\in\left\{2;3;4\right\}\)

e: =>x<10/12-9/12=1/12

=>x=0

f: =>2/3<x<12/6-5/6=7/6

=>x=1

a, \(x\) \(\times\) \(\dfrac{1}{2}\) - \(\dfrac{3}{4}\) = \(\dfrac{5}{6}\)

    \(x\) \(\times\) \(\dfrac{1}{2}\)       = \(\dfrac{5}{6}\) + \(\dfrac{3}{4}\)

   \(x\)   \(\times\) \(\dfrac{1}{2}\)      =  \(\dfrac{19}{12}\)

   \(x\)                = \(\dfrac{19}{12}\) : \(\dfrac{1}{2}\)

  \(x\)                 =   \(\dfrac{19}{6}\)

b, \(x\) : \(\dfrac{1}{2}\) - \(\dfrac{3}{4}\) = \(\dfrac{5}{6}\)

    \(x\): \(\dfrac{1}{2}\)        = \(\dfrac{5}{6}\) + \(\dfrac{3}{4}\)

   \(x\) : \(\dfrac{1}{2}\)        = \(\dfrac{19}{12}\)

   \(x\)              =   \(\dfrac{19}{12}\)  \(\times\) \(\dfrac{1}{2}\) 

   \(x\)              =  \(\dfrac{19}{24}\)

c, \(x\) \(\times\) \(\dfrac{3}{4}\) + \(x\) \(\times\) \(\dfrac{1}{4}\) = \(\dfrac{7}{8}\)

    \(x\) \(\times\) ( \(\dfrac{3}{4}\) + \(\dfrac{1}{4}\)) = \(\dfrac{7}{8}\)

   \(x\)   \(\times\) 1 = \(\dfrac{7}{8}\)

   \(x\)     = \(\dfrac{7}{8}\)

d, \(x\times\) \(\dfrac{3}{4}\) - \(x\) \(\times\) \(\dfrac{1}{4}\) = \(\dfrac{7}{8}\)

    \(x\) \(\times\) ( \(\dfrac{3}{4}\) - \(\dfrac{1}{4}\)) = \(\dfrac{7}{8}\)

    \(x\) \(\times\) \(\dfrac{1}{2}\)  = \(\dfrac{7}{8}\)

   \(x\)           = \(\dfrac{7}{8}\) : \(\dfrac{1}{2}\)

   \(x\)          = \(\dfrac{7}{4}\)

(x-1/2).5/3=7/4-1/2

(x-1/2).5/3=5/4

x-1/2=5/4:5/3

x=3/4+1/2

x=5/4

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

(x+4/3).7/4=23/6

x+4/3=23/6:7/4

x+4/3=46/21

x=46/21-4/3

x=6/7

nhiều quá :((

\(a,2\left(x-5\right)-3\left(x+7\right)=14\)

\(2x-10-3x-21=14\)

\(-x-31=14\)

\(-x=45\)

\(x=45\)

\(b,5\left(x-6\right)-2\left(x+3\right)=12\)

\(5x-30-2x-6=12\)

\(3x-36==12\)

\(3x=48\)

\(x=16\)

\(c,3\left(x-4\right)-\left(8-x\right)=12\)

\(3x-12-8+x=0\)

\(4x-20=0\)

\(4x=20\)

\(x=5\)

Cố nốt nha bn ! 

cảm ơn, bn nha:)))

mà hình như bạn TOP 3 trả lời câu hỏi pải ko nhỉ???

d, \(-7\left(3x-5\right)+2\left(7x-14\right)=28\)

\(\Leftrightarrow-21x+35+14x-28=28\Leftrightarrow-7x=21\Leftrightarrow x=-3\)

e, \(5\left(3-2x\right)+5\left(x-4\right)=6-4x\)

\(\Leftrightarrow15-6x+5x-20=6-4x\Leftrightarrow-5-x=6-4x\)

\(\Leftrightarrow-11+3x=0\Leftrightarrow x=\frac{11}{3}\)

f, \(-5\left(2-x\right)+4\left(x-3\right)=10x-15\)

\(\Leftrightarrow-10+5x+4x-12=10x-15\Leftrightarrow-22+9x=10x-15\)

\(\Leftrightarrow-7-x=0\Leftrightarrow x=-7\)

\(a,\frac{3}{35}-\left[\frac{3}{5}+x\right]=\frac{2}{7}\)

\(\Rightarrow\frac{3}{5}+x=\frac{3}{35}-\frac{2}{7}\)

\(\Rightarrow\frac{3}{5}+x=\frac{3}{35}-\frac{2\cdot5}{35}\)

\(\Rightarrow\frac{3}{5}+x=\frac{3}{35}-\frac{10}{35}=\frac{-7}{35}\)

\(\Rightarrow x=\frac{-7}{35}-\frac{3}{5}=\frac{-7}{35}-\frac{3\cdot7}{35}=\frac{-7}{35}-\frac{21}{35}=\frac{-28}{35}=\frac{-4}{5}\)

\(b,\frac{5}{6}+\frac{1}{6}:x=\frac{3}{4}\)

\(\Rightarrow\frac{1}{6}:x=\frac{3}{4}-\frac{5}{6}\)

\(\Rightarrow\frac{1}{6}:x=\frac{18}{24}-\frac{20}{24}\)

\(\Rightarrow\frac{1}{6}:x=\frac{-2}{24}\)

\(\Rightarrow x=\frac{1}{6}:\frac{-2}{24}=\frac{1}{6}:\frac{-1}{12}=\frac{12}{-6}=\frac{-12}{6}=-2\)

\(c,\left|x-3\frac{4}{7}\right|=-0,5\)

Vì \(\left|x-3\frac{4}{7}\right|\ge0\)mà \(-0,5< 0\)nên \(x\in\varnothing\)

Vậy không có giá trị x thỏa mãn

a)  3/35-(3/5+x)=2/7

<=> 3/5+x=3/35-2/7

<=> 3/5+x=3/35-10/35

<=> 3/5+x=-7/35

<=> 3/5+x=-1/5

<=> x=-1/5-3/5

<=> x=-4/5

Vậy x=-4/5

a) \(\dfrac{29}{60}\)

b)\(1\dfrac{23}{25}\)

c) \(2\dfrac{26}{35}\)