The Second Derivative

$f(x)\quad =\quad 4*{ (1+3x })^{ 5 }\\ \\ f'(x)\quad =\quad 4*5*{ (1+3x })^{ 5-1 }*3\\ f'(x)\quad =\quad 60*{ (1+3x) }^{ 4 }\\ \\ f''(x)\quad =\quad 60*4*{ (1+3x) }^{ 3 }*3\\ f''(x)\quad =\quad 720*{ (1+3x })^{ 3 }\\ \\ f''(\frac { 1 }{ 3 } )\quad =\quad 720*{ (1+3*\frac { 1 }{ 3 } ) }^{ 3 }\\ f''(\frac { 1 }{ 3 } )\quad =\quad 720*{ (1+\frac { 3 }{ 3 } ) }^{ 3 }\\ f''(\frac { 1 }{ 3 } )\quad =\quad 720*{ (2) }^{ 3 }\\ f''(\frac { 1 }{ 3 } )\quad =\quad 720*8\\ f''(\frac { 1 }{ 3 } )\quad =\quad 5760$

Pt: Basta aplicar a regra da cadeia duas vezes na função para encontrar a segunda derivada, e depois substituir o valor de x.

En: Basically, you can use the chain rule twice in the function and after that, you substitute the value of x in the second derivative.