\(\frac{x+1}{35}+\frac{x+3}{33}=\frac{x+5}{31}+\frac{x+7}{29}\\ \Rightarrow\frac{x+1}{35}+\frac{x+3}{33}-\frac{x+5}{31}-\frac{x+7}{29}=0\\ \Rightarrow\left(\frac{x+1}{35}+1\right)+\left(\frac{x+3}{33}+1\right)-\left(\frac{x+5}{31}+1\right)-\left(\frac{x+7}{29}+1\right)=0\\ \Rightarrow\frac{x+36}{35}+\frac{x+36}{33}-\frac{x+36}{31}-\frac{x+36}{29}=0\\ \Rightarrow\left(x+36\right)\left(\frac{1}{35}+\frac{1}{33}-\frac{1}{31}-\frac{1}{29}\right)=0\\ \Rightarrow x+36=0\\ \Rightarrow x=-36\)
Vậy x = -36
