[tex]\bf y=(6+3x)^{\frac{2}{3}}\implies \cfrac{dy}{dx}=\stackrel{chain~rule}{\cfrac{2}{3}(6+3x)^{\frac{2}{3}-1}\cdot (0+3)}
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\cfrac{dy}{dx}=\cfrac{2}{3}(6+3x)^{-\frac{1}{3}}\cdot 3\implies \cfrac{dy}{dx}=2(6+3x)^{-\frac{1}{3}}\implies \cfrac{dy}{dx}=\cfrac{2}{\sqrt[3]{6+3x}}[/tex]
