\(B=\frac{x+5}{2x}-\frac{x-6}{5-x}-\frac{2x^2-2x-50}{2x^2-10x}\)
\(B=\frac{x+5}{2x}-\left(\frac{x-6}{5-x}\right)-\left(\frac{2x^2-2x-50}{2x^2-10x}\right)\)
\(B=\frac{-2x^4+30x^3-150x^2+250x}{-4x^4+40x^3-100x^2}\)
\(B=\frac{-2x^3+30x^2-150x+250}{-4x^3+40x^2-100x}\)
\(B=\frac{-x^3+15x^2-75x+125}{-2x^3+20x^2-50x}\)
\(B=\frac{\left(-x+5\right)\left(x-5\right)\left(x-5\right)}{2x\left(-x+5\right)\left(x-5\right)}\)
\(B=\frac{x-5}{2x}\)