What is the derivative of  y = x [sec (3 - 8x)]?

$\frac{1}{\cos} \left(3 - 8 x\right) \left(1 - 8 x \tan \left(3 - 8 x\right)\right)$
$y = x \left[\sec \left(3 - 8 x\right)\right] = \frac{x}{\cos} \left(3 - 8 x\right)$
$y ' = \frac{1}{\cos} \left(3 - 8 x\right) - 8 \cdot \sin \left(3 - 8 x\right) \cdot \frac{x}{\cos {\left(3 - 8 x\right)}^{2}}$
$= \frac{1}{\cos} \left(3 - 8 x\right) \left(1 - 8 x \tan \left(3 - 8 x\right)\right)$