\(\dfrac{x}{x+1}:\dfrac{x+2}{x+1}:\dfrac{x+3}{x+2}:\) ________ \(=\dfrac{x}{x+6}\)
\(\Rightarrow\dfrac{x}{x+1}.\dfrac{x+1}{x+2}.\dfrac{x+2}{x+3}.\) ________\(=\dfrac{x}{x+6}\)
\(\Rightarrow\dfrac{x}{x+3}\)______ = \(\dfrac{x}{x+6}\)
\(\Rightarrow\) _______ = \(\dfrac{x+3}{x+6}\)