\(\dfrac{26}{2\sqrt{3}-5}\)
\(=\dfrac{26\left(2\sqrt{3}+5\right)}{\left(2\sqrt{3}-5\right)\left(2\sqrt{3}+5\right)}\)
\(=\dfrac{26\left(2\sqrt{3}+5\right)}{\left(2\sqrt{3}\right)^2-5^2}\)
\(=\dfrac{26\left(2\sqrt{3}+5\right)}{12-25}\)
\(=\dfrac{26\left(2\sqrt{3}+5\right)}{-13}\)
\(=-2\left(2\sqrt{3}+5\right)\)
\(=-4\sqrt{3}-10\)
\(=\dfrac{26\left(2\sqrt{3}+5\right)}{12-25}=-2\left(2\sqrt{3}+5\right)=-4\sqrt{3}-10\)