Answer
$\displaystyle \frac{dy}{dx}=36x^{2}-3$
Work Step by Step
Set: $f(x)=3x\ \ g(x)=4x^{2}-1$
$f^{\prime}(x)=3\qquad g^{\prime}(x)=4(2x)-0=8x$
$\displaystyle \frac{dy}{dx}=\frac{d}{dx}[f(x)g(x)]$= ... product rule ...
$= f^{\prime}(x)g(x)+f(x)g^{\prime}(x)$
$=3(4x^{2}-1)+3x(8x)$
$=12x^{2}-3+24x^{2}$
$=36x^{2}-3$
