-1 \le \frac{x^2+x}{x^2-5x+4} \\
\frac{x^2+x}{x^2-5x+4} \geq -1 \\
\frac{x^2+x}{x^2-5x+4} +1 \geq 0 \\
\frac{x^2+x+x^2-5x+4}{x^2-5x+4} \geq 0 \\
\frac{2x^2-4x+4}{x^2-5x+4} \geq 0