If f(x)=(8x4)4(7x2+7)3\displaystyle {f{{\left({x}\right)}}}={\left({8}{x}-{4}\right)}^{{{4}}}\cdot{\left({7}{x}^{{2}}+{7}\right)}^{{{3}}}, find f(x)\displaystyle {f}'{\left({x}\right)} using logarithmic differentiation.