$$ \begin{aligned} n-8 &= 6\cdot3&& \text{move the $ \color{blue}{ 18 } $ to the left side and $ \color{blue}{ -8 }$ to the right} \\[1 em]n-18 &= 8&& \text{ move -18 to the right } \\[1 em]n &= 8+18&& \\[1 em]n &= 26&& \\[1 em]n &= 26&& \\[1 em] \end{aligned} $$