\(\dfrac{3}{2x+10}+\dfrac{3}{x-5}-\dfrac{2x}{x^2-25}\)
\(=\dfrac{3\left(x-5\right)}{2\left(x+5\right)\left(x-5\right)}+\dfrac{6\left(x+5\right)}{2\left(x+5\right)\left(x-5\right)}-\dfrac{4x}{2\left(x+5\right)\left(x-5\right)}\)
\(=\dfrac{3x-15+6x+30-4x}{2\left(x+5\right)\left(x-5\right)}\)
\(=\dfrac{5x+15}{2\left(x+5\right)\left(x-5\right)}\)