\(331=\left(x+140\right).\frac{1}{x}+260\)

\(\left(x+140\right).\frac{1}{x}+260-331=0\)

\(\left(x+140\right).\frac{1}{x}-71=0\)

\(\frac{1}{x}.x+\frac{1}{x}.140-71=0\)

\(1+\frac{1}{x}.140=0\)

\(\frac{1}{x}.140=0-1=-1\)

\(\frac{1}{x}=-\frac{1}{140}\Rightarrow x=1:-\frac{1}{140}=-140\)

\(71+260=\frac{x+140+260x}{x }\)
\(331=\frac{261x+140}{x}\)
\(331x=261x+140\)
\(70x=140\)
\(x=2\)
Nhớ thêm dấu khi và chỉ khi <=> trước mỗi phép kia nhé, mình lười quá không ghi

       331= [x+140]:x+260 hay [x+140]:x+260=331

 x/x + 140/x + 260 = 331

 1 + 140/x + 260 = 331

 1 + 140/x         = 331 - 260

 1 + 140/x         =  71

       140/x         = 71 - 1

       140/x         = 70

=> x = 140 : 70 = 2

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

\(\frac{x+140}{x+260}=136,4\)

\(\Rightarrow\)\(x+140=\left(x+260\right).136,4\)

\(\Rightarrow x+140=136,4x+35464\)

\(\Rightarrow x-136,4x=35464-140\)

\(\Rightarrow-135,4x=35324\)

\(\Rightarrow x=....\)

a, ( x . 0,25+1999).2000=(53+1999).2000

=> 500x + 1999 . 2000 = 53 . 2000 + 1999 . 2000

=> 500x = 53 . 2000 + 1999 . 2000 - 1999 .2000

=> 500x = 53 . 2000

=> x = 53 . 2000 : 500

=> x = 53 . 4

=> x = 212 

x=2nha. Nhớ đó

a) 3/x-7 = 27/135

3/x-7 = 3/15

x - 7 = 15

x = 15 + 7

x = 22

a) \(\frac{3}{x-7}=\frac{27}{135}\)

\(\Rightarrow\)\(\left(x-7\right).27=3.135\)

\(\Rightarrow\)\(\left(x-7\right).27=405\)

\(\Rightarrow\)\(x-7=15\)

\(\Rightarrow\)\(x=22\)

Vậy \(x=22\)

b ) \(71+65.4=\frac{x+140}{x}+260\)

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

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

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

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

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

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

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

\(x=140\div70\)

\(x=20\)

Vậy \(x=20\)

#TQY

   331= [x+140]:x+260 hay [x+140]:x+260=331

 x/x + 140/x + 260 = 331

 1 + 140/x + 260 = 331

 1 + 140/x         = 331 - 260

 1 + 140/x         =  71

       140/x         = 71 - 1

       140/x         = 70

=> x = 140 : 70 = 2

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

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

x + 140/x + 260 = 71 + 260

x + 140/x = 71

x/x + 140/x  = 71

1 + 140/x = 71

140/x = 71 - 1

140/x = 70

     x = 140/70

     x = 2

   ích=2

nhớ nha !

71+ 65 x 4 = (X+14) /X + 260

71 + 260 = X : X + 14 : X + 260

71 = 1 + 14 : X (Cùng bớt 2 vế đi 260)

1 + 14 : X = 71 (đảo vế)

14 : X = 71 - 1

14 : X = 70

X = 14 : 70

X = 0,2

mik nha !!!

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