Giải :
\(\dfrac{x+11}{89}+\dfrac{x+13}{87}-\dfrac{x+15}{85}-\dfrac{x+17}{83}=0\\ =>\left(\dfrac{x+11}{89}+1\right)+\left(\dfrac{x+13}{87}+1\right)-\left(\dfrac{x+15}{85}+1\right)-\left(\dfrac{x+17}{83}+1\right)=0\\ =>\left(\dfrac{x+11+89}{89}\right)+\dfrac{x+13+87}{87}-\dfrac{x+15+85}{85}-\dfrac{x+17+83}{83}=0\\ =>\dfrac{x+100}{89}+\dfrac{x+100}{87}-\dfrac{x+100}{85}-\dfrac{x+100}{83}=0\\ =>\left(x+100\right)\left(\dfrac{1}{89}+\dfrac{1}{87}-\dfrac{1}{85}-\dfrac{1}{83}\right)=0\\ =>\left[{}\begin{matrix}x+100=0\\\dfrac{1}{89}+\dfrac{1}{87}-\dfrac{1}{85}-\dfrac{1}{83}=0\left(voli\right)\end{matrix}\right.=>x=-100\)