\(\frac{x+1}{9}+\frac{x+2}{8}+\frac{x+3}{7}+...+\frac{x+9}{1}=-9\)
\(\left(\frac{x+1}{9}+1\right)+\left(\frac{x+2}{8}+1\right)+\left(\frac{x+3}{7}+1\right)+...+\left(\frac{x+9}{1}+1\right)=0\)
\(\frac{x+10}{9}+\frac{x+10}{8}+\frac{x+10}{7}+...+\frac{x+10}{1}=0\)
\(\left(x+10\right).\left(\frac{1}{9}+\frac{1}{8}+\frac{1}{7}+...+1\right)=0\)
vì \(\frac{1}{9}+\frac{1}{8}+\frac{1}{7}+...+1\ne0\)
\(\Rightarrow x+10=0\)
\(\Rightarrow x=-10\)
\(\left(\frac{x+1}{9}+1\right)+\left(\frac{x+2}{8}+1\right)+...+\left(\frac{x+9}{1}+1\right)=-9+9\)
\(\Rightarrow\frac{x+10}{9}+\frac{x+10}{8}+...+\frac{x+10}{1}\) =
