Power and chain rule:
[tex]\dfrac{\mathrm d(2x^2+5x)^6}{\mathrm dx}=6(2x^2+5x)^5\dfrac{\mathrm d(2x^2+6x)}{\mathrm dx}[/tex]
Addition and power rule:
[tex]\dfrac{\mathrm d(2x^2+6x)}{\mathrm dx}=\dfrac{\mathrm d(2x^2)}{\mathrm dx}+\dfrac{\mathrm d(6x)}{\mathrm dx}=4x+6[/tex]
Putting everything together, we get
[tex]\dfrac{\mathrm d(2x^2+5x)^6}{\mathrm dx}=6(2x^2+5x)^5(4x+6)[/tex]
