\(71+65.4=x+140:x+260\)

\(331=x+140:x+260\)

\(331-260=x+260:x\)

\(71=x+260:x\)

\(71-x=260:x\)
tới đây tui ko biết

Ta có: \(71+\left(65\times4\right)=\frac{y+140}{y+260}\)

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

\(\Leftrightarrow331\left(y+260\right)=y+140\)

\(\Leftrightarrow331y+86060=y+140\)

\(\Leftrightarrow331y-y=140-86060\)

\(\Leftrightarrow330y=-85920\)

\(\Leftrightarrow y=\frac{-85920}{330}=\frac{-2864}{11}\)

hình như bn viết ngược 

                     bài giải

x + 140/x + 260=331

x nhân 2 + 140 =331-260=71

x nhân 2 =71 : 140 =0,50

      x= 0,50 : 2

      x=0,25

          hok tốt

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

=> 71 + 260 = \(\frac{x+140}{x+260}\)

=> \(331=\frac{x+140}{x+260}\)

=> \(331.\left(x+260\right)=x+140\)

=> \(331x+86060=x+140\)

=> \(331x-x=-86060+140\)

=>330x =- 85920

=> x = -2864/11

=> \(330x=-85920\)

\(a.\left(x\times0,25+1999\right)\times2000=2052\times2000\\ \left(x\times0,25+1999\right)\times2000=4104000\\ x\times0,25+1999=4104000:2000\\ x\times0,25+1999=2052\\ x\times0,25=2052-1999\\ x\times0,25=53\\ x=53:0,25\\ x=212\)

#)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

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

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

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

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

\(71x=x+140\)

\(71x-x=140\)

\(70x=140\)

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

\(x=2\)