\(71+65\times4=\left(x+140\right):x+260\)

\(71+260=\left(x+140\right):x+260\)

\(71+260-260=\left(x+140\right):x\)

\(71=\left(x+140\right):x\)

\(71x=x+140\)

\(71x-x=140\)

\(70x=140\)

\(x=2\)

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

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

\(x+140=71x\)

\(x-71x=-140\)

\(-70x=-140\)

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

Vậy \(x=2\)

mạnh làm sai

\(\frac{x+140}{x}\)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 *

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

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

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

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

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

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

\(\Leftrightarrow140=x70\)

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

\(71+65\cdot4=\frac{x+140}{x}+260\)

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

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

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

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

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

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

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

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

\(\Rightarrow71x=x+140\)

\(\Rightarrow71x-x=140\)

\(\Rightarrow70x=140\)

\(\Rightarrow x=2\)