$$q+20 = 3\cdot(9-2q)$$

$$ \begin{aligned} q+20 &= 3\cdot(9-2q)&& \text{simplify right side} \\[1 em]q+20 &= 27-6q&& \\[1 em]q+20 &= -6q+27&& \text{move the $ \color{blue}{ -6q } $ to the left side and $ \color{blue}{ 20 }$ to the right} \\[1 em]q+6q &= 27-20&& \text{simplify left and right hand side} \\[1 em]7q &= 7&& \text{ divide both sides by $ 7 $ } \\[1 em]q &= \frac{7}{7}&& \\[1 em]q &= 1&& \\[1 em] \end{aligned} $$

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