\(\frac{2x-1}{-9}=\frac{4}{1-2x}\\ \Leftrightarrow\frac{1-2x}{9}=\frac{4}{1-2x}\\ \Leftrightarrow\left(1-2x\right)^2=4\cdot9\\ \left(1-2x\right)^2-36=0\\ \left(1-2x-6\right)\left(1-2x+6\right)=0\\ \left(-2x-5\right)\left(7-2x\right)=0\\ \Rightarrow\left[{}\begin{matrix}-2x-5=0\\7-2x=0\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=-\frac{5}{2}\\x=\frac{7}{2}\end{matrix}\right.\\ Vậy...\)