Solve -b^3+6x^2-2x^2/6(x-6)(x+6)=0

$$\frac { - b ^ { 3 } + 6 x ^ { 2 } - 2 x ^ { 2 } } { 6 ( x - 6 ) ( x + 6 ) } = 0$$

Solve for b (complex solution)

$$b=\sqrt[3]{4}e^{\frac{2\pi i}{3}}x^{\frac{2}{3}}$$

$$b=\sqrt[3]{4}x^{\frac{2}{3}}$$

$$b=\sqrt[3]{4}e^{\frac{4\pi i}{3}}x^{\frac{2}{3}}\text{, }x\neq -6\text{ and }x\neq 6$$

Solve for x (complex solution)

$$\left\{\begin{matrix}x=\frac{b^{\frac{3}{2}}}{2}\text{, }&b\neq 2\sqrt[3]{18}\text{ and }b\neq 2\sqrt[3]{18}e^{\frac{2\pi i}{3}}\\x=-\frac{b^{\frac{3}{2}}}{2}\text{, }&b\neq 2\sqrt[3]{18}\text{ and }b\neq 2\sqrt[3]{18}e^{\frac{4\pi i}{3}}\text{ and }b\neq 2\sqrt[3]{18}e^{\frac{2\pi i}{3}}\end{matrix}\right.$$

Solve for b

$$b=\sqrt[3]{4}x^{\frac{2}{3}}$$

$$|x|\neq 6$$

Solve for x

$$\left\{\begin{matrix}x=-\frac{b^{\frac{3}{2}}}{2}\text{, }&b\neq 12^{\frac{2}{3}}\text{ and }b\geq 0\text{ and }b\neq 2\sqrt[3]{18}\\x=\frac{b^{\frac{3}{2}}}{2}\text{, }&b\neq 12^{\frac{2}{3}}\text{ and }b\geq 0\end{matrix}\right.$$