If ( 3/5 )^3 × ( 3/5 )^ - 6 = ( 3/5 )^2x - 1 , then x is equal to?

Answer: Option C

$$\begin{array}{rl}& {\left(\frac{3}{5}\right)}^3\times {\left(\frac{3}{5}\right)}^{-6}={\left(\frac{3}{5}\right)}^{2x-1}\\ & \Rightarrow {\left(\frac{3}{5}\right)}^{3-6}={\left(\frac{3}{5}\right)}^{2x-1}\\ & \Rightarrow -3=2x-1\\ & \Rightarrow 2x=-2\\ & \Rightarrow x=-1\end{array}$$