($\dfrac{3x-2}{\sqrt[]{2x+5}}$)$'$
= $\dfrac{(3x-2)'.\sqrt[]{2x+5}-(3x-2).\sqrt[]{2x+5}'}{\sqrt[]{2x+5}^2}$
= $\dfrac{3.\sqrt[]{2x+5}-(3x-2).\dfrac{(2x+5)'}{2.\sqrt[]{2x+5}}}{\sqrt[]{2x+5}^2}$
= $\dfrac{3.\sqrt[]{2x+5}-(3x-2).\dfrac{2}{2.\sqrt[]{2x+5}}}{\sqrt[]{2x+5}^2}$
= $\dfrac{3.\sqrt[]{2x+5}-\dfrac{6x-4}{2.\sqrt[]{2x+5}}}{\sqrt[]{2x+5}^2}$