\(x+30\%x=1,31< =>x+0,3x=1,31\)
\(< =>1,3x=1,31=>x=\dfrac{1,31}{1,3}=\dfrac{131}{130}\)
\(x+30\%x=1.31\\\Leftrightarrow\left(1+0,3\right)x=1,31\\ \Leftrightarrow1,3x=1,31\\ \Rightarrow x=\dfrac{131}{130}\)
\(x+30\%x=1,31\)
\(x.\left(1+\dfrac{3}{10}\right)=\dfrac{131}{100}\)
\(x.\dfrac{13}{10}=\dfrac{131}{100}\)
\(x=\dfrac{131}{100}:\dfrac{13}{10}\)
\(x=\dfrac{131}{130}\)