How much numbers In-dice

$\begin{aligned} 2\sqrt[4x]{x^{3x}} & = 3\sqrt[2x]{x^{4x}}\\ 2{\left(x^{3x}\right)}^{\tfrac{1}{4x}} & = 3{\left(x^{4x}\right)}^{\tfrac{1}{2x}}\\ 2x^{\tfrac{3}{4}} & = 3x^2\\ \dfrac{2}{3} & = \dfrac{x^2}{x^{\tfrac{3}{4}}}\\ \dfrac{2}{3} & = x^{2 - \tfrac{3}{4}}\\ \dfrac{2}{3} & = x^{\tfrac{5}{4}}\\ \text{Raising power of 4 on both sides}:-\\ \dfrac{16}{81} & = x^5\\ \text{Raising root of 5 on both sides}:-\\ x & = \sqrt[5]{\dfrac{16}{81}}\\ \therefore a + b & = 16 + 81\\ & = \boxed{97} \end{aligned}$