Gọi phân số đó là \(\dfrac{a-11}{a}\)(a \(\ne\) 11). Ta có:
\(\dfrac{a-11-17}{a+4}=\dfrac{a}{a-11}\)
\(\Rightarrow\left(a-28\right)\left(a-11\right)=a\left(a+4\right)\)
\(\Rightarrow a^2-39a+308=a^2+4a\)
\(\Rightarrow308-39a=4a\)
\(\Rightarrow308=43a\)
\(\Rightarrow a=\dfrac{308}{43}\)
\(\Rightarrow\dfrac{a-11}{a}=\dfrac{-250}{93}\)
Vậy...