Let $ f(x) = 4\sqrt x-2$

$ f'(x) = \large\frac{d}{dx}$$(4\sqrt x-2)= \large\frac{d}{dx}$$(4\sqrt x)- \large\frac{d}{dx}$$(2)$

$ = 4 \large\frac{d}{dx}$$\bigg( x^{\large\frac{1}{2}} \bigg)$$-0=4 \bigg( \large\frac{1}{2}x^{\large\frac{1}{2}-1}\bigg)$

$\bigg( 2x^{-\large\frac{1}{2}}$$ \bigg)$$=\Large\frac{2}{\sqrt x}$