`(x+2)/(x-2)-2/(x^2-2x)=1/x`

ĐK:`x ne 0,x ne +-2`

Nhân 2 vế với `x^2-2x ne 0` ta có pt

`x(x+2)-2=x(x-2)`

`<=>x^2+2x-2=x^2-2x`

`<=>4x=2`

`<=>x=1/2.(tm)`

Vậy `S={1/2}`

\(x:\left[\dfrac{8}{5}\cdot\left(\dfrac{2}{3}\right)^2-\dfrac{2}{5}\right]=\dfrac{15}{7}+\dfrac{6}{5}\left[\left(2\dfrac{1}{7}\right)^2-\dfrac{50}{49}\right]\)

\(\Leftrightarrow x:\left[\dfrac{32}{45}-\dfrac{18}{45}\right]=\dfrac{15}{7}+\dfrac{6}{5}\cdot\left(\dfrac{225}{49}-\dfrac{50}{49}\right)\)

\(\Leftrightarrow x:\dfrac{14}{45}=\dfrac{15}{7}+\dfrac{6}{5}\cdot\dfrac{25}{7}\)

\(\Leftrightarrow x:\dfrac{14}{45}=\dfrac{45}{7}\)

\(\Leftrightarrow x=2\)

a) \(\left|x\right|+x\)

Vì \(\left|x\right|\ge0\) nên ta có 3TH:

TH1: \(x>0\)

\(\Rightarrow\left|x\right|+x=2x\)

TH2: \(x=0\)

\(\Rightarrow\left|x\right|+x=0\)

TH3: \(x< 0\)

\(\Rightarrow\left|x\right|+x=0\)

b) \(N=\left|x\right|:x\)

Vì \(\left|x\right|\ge0\) và \(x\ne0\) nên ta có 2TH:

TH1: \(x>0\)

\(\Rightarrow\left|x\right|:x=1\)

TH2: \(x< 0\)

\(\Rightarrow\left|x\right|:x=-1\)

a: \(M=\left|x\right|+x=\left[{}\begin{matrix}x+x=2x\left(x\ge0\right)\\-x+x=0\left(x< 0\right)\end{matrix}\right.\)

b: \(N=\left|x\right|:x=\pm1\)

\(75\%x+\frac{3}{4}x+x=30\)

\(\Leftrightarrow\left(75\%+\frac{3}{4}+1\right)x=30\)

\(\Leftrightarrow\frac{5}{2}x=30\)

\(\Leftrightarrow x=30:\frac{5}{2}\)

\(\Leftrightarrow x=12\)

đổi 75%=3/4.Ta có:

3/4xX+3/4xX+X=30

(3/4+3/4+1)xX=30

    5/2     x    X=30

                 X  = 30:5/2

                X   = 12

\(75\%\times x+\frac{3}{4}\times x+x=30\)

\(\frac{3}{4}\times x+\frac{3}{4}\times x+1\times x=30\)

\(\left(\frac{3}{4}+\frac{3}{4}+1\right)\times x=30\)

\(\frac{5}{2}\times x=30\)

\(x=30\div\frac{5}{2}\)

\(x=12\)

giá xăng từ 20 000 đồng lên 21 000 đồng 1 lít . hỏi giá xăng tăng bao nhiêu phần trăm? 

= 75% x X + 3/4 x X + X = 30

= X x (3/4 + 3/4 + 1) = 30

= X x 10/4 = 30

= X = 30 : 10/4

X = 12

0,75 x X + 0,75 x X + X = 30

X x ( 0,75 + 0,75 + 1 ) = 30

X x 2,5 = 30

X = 30 : 2,5

X = 12

75%xX+3/4xX+X=30

<=>3/4xX+3/4xX+X=30

<=>10/4xX=30

<=>10xX=120

<=>X=120/10=12

Vậy X=12

0,75x + 0,75x = 30

0,75 . 2x = 30

2x = 40

x = 20

\(75\%\cdot x+\frac{3}{4}\cdot x+x=30\)

\(x\cdot\left(\frac{3}{4}+\frac{3}{4}+1\right)=30\)

\(x\cdot\frac{5}{2}=30\)

\(x=30\cdot\frac{2}{5}\)

\(x=12\)

\(75\%\cdot x+\frac{3}{4}\cdot x+x=30\)

\(\frac{3}{4}\cdot x+\frac{3}{4}\cdot x+x=30\)

\(\left(\frac{3}{4}+\frac{3}{4}\right)\cdot x+x=30\)

\(\frac{3}{2}\cdot x+x=30\)

\(\frac{3}{2}\cdot x+\frac{1}{1}\cdot x=30\)

\(\left(\frac{3}{2}+\frac{1}{1}\right)\cdot x=30\)

\(\frac{5}{2}\cdot x=30\)

\(x=30\text{ : }\frac{5}{2}\)

\(x=12\)