Answer
$\frac{dy}{dx} = 48(64x^{2} +1 - 16x)=48(8x-1)^{2}$
Work Step by Step
$\frac{dy}{du} = \frac{d(2u^{3})}{du} = 6u^{2}$
And,
$\frac{du}{dx} = \frac{d(8x-1)}{dx} = 8$
So,
$\frac{dy}{dx} = \frac{dy}{du}*\frac{du}{dx}$
$\frac{dy}{dx} = 48u^{2}$
$\frac{dy}{dx} = 48(8x-1)^{2}$
$\frac{dy}{dx} = 48(64x^{2} +1 - 16x)$