\(\frac{3}{2x+5}-\frac{40}{4x^2-25}+\frac{1}{2x-5}\)
\(=\frac{3\cdot\left(2x-5\right)}{4x^2-25}-\frac{40}{4x^2-25}+\frac{2x+5}{4x^2-25}\)
\(=\frac{6x-15-40+2x+5}{\left(2x+5\right)\cdot\left(2x-5\right)}=\frac{8x-50}{\left(2x+5\right)\cdot\left(2x-5\right)}\)