\(\dfrac{x+27}{343}+\dfrac{x+28}{342}=\dfrac{x+121}{249}+\dfrac{x+120}{250}\)
\(\Rightarrow\left(\dfrac{x+27}{343}+1\right)+\left(\dfrac{x+28}{342}+1\right)=\left(\dfrac{x+121}{249}+1\right)+\left(\dfrac{x+120}{250}+1\right)\)
\(\Rightarrow\dfrac{x+370}{343}+\dfrac{x+370}{342}-\dfrac{x+370}{249}-\dfrac{x+370}{250}=0\)
\(\Rightarrow\left(x+370\right)\left(\dfrac{1}{343}+\dfrac{1}{342}-\dfrac{1}{249}-\dfrac{1}{250}\right)=0\)
Mà \(\dfrac{1}{343}+\dfrac{1}{342}-\dfrac{1}{249}-\dfrac{1}{250}\ne0\)
\(\Rightarrow x+370=0\Rightarrow x=-370\)
Vậy x = -370
\(\dfrac{x+27}{343}+\dfrac{x+28}{342}=\dfrac{x+121}{249}+\dfrac{x+120}{250}\)
\(\Rightarrow\dfrac{x+27}{343}+\dfrac{x+28}{342}-\dfrac{x+121}{249}-\dfrac{x+120}{250}=0\)
\(\Rightarrow\left(\dfrac{x+27}{343}+1\right)+\left(\dfrac{x+28}{342}+1\right)-\left(\dfrac{x+121}{249}+1\right)-\left(\dfrac{x+120}{250}+1\right)=0\)
\(\Rightarrow\dfrac{x+370}{343}+\dfrac{x+370}{342}-\dfrac{x+370}{249}-\dfrac{x+370}{250}=0\)
\(\Rightarrow\left(x+370\right)\left(\dfrac{1}{343}+\dfrac{1}{342}-\dfrac{1}{249}-\dfrac{1}{250}\right)=0\)
\(\Rightarrow x+370=0\Rightarrow x=-370\)