What should come in place of both x in the equation x 128 = 162 x

Answer: Option A

$$\begin{array}{rl}& \text{Let}\frac{x}{\sqrt{128}}=\frac{\sqrt{162}}{x}\\ & \text{Then}{x}^2=\sqrt{128\times 162}\\ & =\sqrt{64\times 2\times 18\times 9}\\ & =\sqrt{8^2\times 6^2\times 3^2}\\ & =8\times 6\times 3\\ & =144\\ & \therefore x=\sqrt{144}=12\end{array}$$