If x + 116x = 3, then the value of 16x^3 + 1256x^3 is:

Answer: Option A

$$\begin{array}{rl}& x+\frac{1}{16x}=3\\ & 2x+\frac{1}{8x}=6\\ & \text{Cube both side}\\ & 8x^3+\frac{1}{512x^3}+3\times 2\times \frac{1}{8}\times 6=216\\ & 8x^3+\frac{1}{512x^3}=216-\frac{9}{2}\\ & \text{Multiply by ’2’ both side}\\ & 16x^3+\frac{1}{256x^3}=432-9=423\end{array}$$