\(\dfrac{x^2+1}{4x^2}=\dfrac{2x-1}{x+1}\)
\(\Leftrightarrow x^3+x^2+x+1=8x^3-4x^2\)
\(\Leftrightarrow-7x^3+5x^2+x+1=0\)
\(\Leftrightarrow7x^3-5x^2-x-1=0\)
\(\Leftrightarrow7x^3-7x^2+2x^2-2x+x-1=0\)
\(\Leftrightarrow\left(x-1\right)\left(7x^2+2x+1\right)=0\)
\(\Leftrightarrow x=1\)