tolong jawab + caranya

[tex]turunan\ =0\\ f'(x)=0\\ 12x^{2}-60x+54=0\\ 2x^{2}-10x+9=0\\ \\ \\ x1=\frac {-b+\sqrt {b^{2}-4ac}}{2a}\\ x1=\frac {10+\sqrt{100-72}}{4}\\ x1=\frac {10+\sqrt{28}}{4}\\ x1=\frac {10+2\sqrt{7}}{4}\\ x1=\frac {5+\sqrt{7}}{2}\\ x2=\frac {5-\sqrt{7}}{2}}\\ jika\ volume\ max\ maka\ yang\ diambil\ x=\frac {5+\sqrt{7}}{2} [/tex]