1.4./x-5/-54=-34

4./x-5/=-34+54

4./x-5/=20

/x-5/=20:4

/x-5/=5

=>x-5=5 va x-5=-5

TH1:x-5=-5

=>x=0

TH2:x-5=5

=>x=10

2. /x-1/+(-5)=2

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

/x-1/=7

=>x-1=7 va x-1=-7

TH1: x-1=7

=>x=8

TH2:x-1=-7

=>x=-6

vay x=-6 hoac x=8

1) (-10)-|5-x|=(-12)

|5-x|=(-10)-(-12)

|5-x|=2

\(\Rightarrow\left[{}\begin{matrix}5-x=2\\5-x=\left(-2\right)\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=7\end{matrix}\right.\)

Vậy:............

a) Đặt x^2+2x+2=t

\(\frac{4}{t-1}+\frac{3}{t+1}=\frac{3}{2}\Leftrightarrow\frac{4t+4+3t-3}{t^2-1}=\frac{7t+1}{t^2-1}=\frac{3}{2}\)

\(\Leftrightarrow14t+2=3t^2-3\Leftrightarrow3t^2-14t-5=3t\left(t-5\right)+t-5=0\)\(\Leftrightarrow\left(t-5\right)\left(3t+1\right)=0\Rightarrow\left[\begin{matrix}t=5\\t=-\frac{1}{3}\left(loai\right)\end{matrix}\right.\)

Với t=5 ta có (x+1)^2=4\(\Rightarrow\left[\begin{matrix}x+1=2\\x+1=-2\end{matrix}\right.\Rightarrow\left\{\begin{matrix}x=1\\x=-3\end{matrix}\right.\)

Sao lai co 3t(t-5) ,cho do thua

/

Vậy /

mình không biết cách làm, nhưng mình biết x = 7,5

\(4x-3-x-5-=x+2-2x+2.10\)

\(3x-8=x+2-2x+20\)

\(3x=x+10-2x+20\)

\(3x=-x+30\)

\(4x=30\)

\(x=\frac{30}{4}=7,5\)

Ta có

(2x+5/4)³=-27=-3³

=> 2x+5/4=-3

=>2x=-3-5/4

=>x=-17/4:2=-17/2

KL

(3-4x/5)²=100/49=(10/7)²

=>3-4x/5=10/7

=>3-4x=50/7

=>4x=-29/7

=>x=-29/28

KL

a) x - \(\frac{1}{8}\)= \(\frac{7}{3}\)x \(\frac{21}{4}\)

   x - \(\frac{1}{8}\)= \(\frac{49}{4}\)

             x = \(\frac{49}{4}\)+ \(\frac{1}{8}\)

             x = 98

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

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

              x = \(\frac{3}{8}\)

c) \(\frac{103}{10}\) - x = \(\frac{4}{5}\)

                    x = \(\frac{103}{10}\)- \(\frac{4}{5}\)

                    x = \(\frac{19}{5}\)

d) x = 51 x \(\frac{4}{17}\)

    x = \(12\)

Vậy chị kết luận ngắn gọn là:

a)=98

b)=3/8

c)=19/5

d)=12

cho mình sửa đề 1 chút:

Tìm số nguyên x biết: ( 2x - 1) + ( 4x - 2) + ( 6x - 3) + .............+( 400x - 200) = 5 + 10 + 15 + .......+ 1000 .

x = 0 

a) 25-5x+3-4=0

=> 24-5x=0

=> 5x=24

=> x=\(\dfrac{24}{5}\)

b) 259-51/4x+3/=100.3+10=310

=> -51/4x+3/=310-259=51

=> /4x+3/=-51 (1)

Vi /4x+3/≥0 (2)

Tu (1)(2) => pt vo nghiem

c) 7x-21-15+5x=6

=> 12x-36-6=0

=> 12x-42=0

=> 12x=42

=> x=\(\dfrac{42}{12}=\dfrac{7}{2}\)