#)Giải :

           \(71+65.4=\frac{x+140}{x}+260\)

\(\frac{x+140}{x}+260=71+65.4\)

\(\frac{x+140}{x}+260=71+260\)

             \(\frac{x+140}{x}=71\)

         \(\frac{x}{x}+\frac{140}{x}=71\)

           \(1+\frac{140}{x}=71\)

                   \(\frac{140}{x}=71-1\)

                   \(\frac{140}{x}=70\)

                          \(x=140:70\)

                          \(x=2\)

             #~Will~be~Pens~#

\(71+65.4=\frac{x+140}{x}+260\)

\(\Rightarrow\frac{x+140}{x}+260=71+65.4\)

\(\frac{x+140}{x}+260=331\)

\(\frac{x+140}{x}=331-260=71\)

\(\frac{x}{x}+\frac{140}{x}=71\)

\(1+\frac{140}{x}=71\)

\(\frac{140}{x}=71-1=70\)

\(x=\frac{140}{70}=2\)

Vậy x=2

\(71+65\text{ x }4=\frac{x+140}{x}+260\)

\(\frac{x+140}{x}+260=71+65\text{ x }4\)

\(\frac{x+140}{x}+260=71+260\)

\(\frac{x+140}{x}=71\)

\(71x=x+140\)

\(71x-x=140\)

\(70x=140\)

\(x=140\text{ : }70\)

\(x=2\)

\(\frac{x+140}{x}\)phân tích ra thành \(\frac{x}{x}+\frac{140}{x}\)đó Ngọc Nguyễn Minh 

x=2 đó LINH 

x=2 bạn nha

x=400x331

x=132400

tích nha!mk tích bn rùi đó

71+260=x/(140+260)

331=x/400

x=400x331=132400

331=x+140:x+260

331=x: [140+260]

331=x:400

x=331 nhân 400

x=132 400

   hok tốt

x = 2

* Cách giải lên lớp 6 học *

\(71+65\times4=\frac{x+140}{x}+260\)

\(\Leftrightarrow331=\frac{x+140}{x}+260\)

\(\Leftrightarrow71=\frac{x+140}{x}\)

\(\Leftrightarrow x+140=71.x\)

\(\Leftrightarrow140=71.x-x\)

\(\Leftrightarrow140=x\left(71-1\right)\)

\(\Leftrightarrow140=x70\)

\(\Leftrightarrow x=140:70=2\)

71 + 65 x 4 = x + 140/x + 260

x + 140/x + 260 = 71+ 65 x4

x + 140/x + 260 = 71 + 260

x + 140/x = 71

x/x + 140/x = 71

140/x = 71 - 1

140/x = 70

x = 140 : 70

x = 2