Differentiating $x^2 \sqrt{2x+5}-6$ How do I differentiate this function: f(x)= $x^2  \sqrt{2x+5}-6$
I had: I had $2x\sqrt{2x+5} + x^2  \dfrac{1}{2\sqrt{2x+5}}$ but the correction model said it was I had $2x\sqrt{2x+5} + x^2  \dfrac{2}{2\sqrt{2x+5}}$

$$
\begin{eqnarray*}
  y &=& x^2(2x+5)^{1/2} - 6 \\
  \frac{dy}{dx} &=& \frac{d}{dx} \Big[ x^2(2x+5)^{1/2} \Big] - \frac{d}{dx}\Big[ 6 \Big], \qquad \textrm{Sum/Difference Rule}\\
  &=& \frac{d}{dx}\Big[x^2\Big](2x+5)^{1/2} + x^2\frac{d}{dx}\Big[(2x+5)^{1/2}\Big] - 0, \qquad \textrm{Product Rule}\\
  &=& 2x(2x+5)^{1/2} + x^2\left( \frac{1}{2}(2x+5)^{-1/2}\cdot 2\right),
  \qquad \textrm{Chain Rule}\\
  &=& 2x\sqrt{2x+5} + \frac{ x^2}{\sqrt{2x+5}}, \qquad \textrm{simplification.}
\end{eqnarray*}
$$
