If _10125 + _108 = x, then x is equal to -

Answer: Option D

$$\begin{array}{rl}& {\log }_{10}125+{\log }_{10}8=x\\ & \Rightarrow {\log }_{10}\left(125\times 8\right)=x\\ & \Rightarrow x={\log }_{10}\left(1000\right)\\ & \Rightarrow x={\log }_{10}{\left(10\right)}^3\\ & \Rightarrow x=3{\log }_{10}10\\ & \Rightarrow x=3\end{array}$$