$$ \begin{aligned} -2(x-9)+7 &= 3x-15&& \text{simplify left side} \\[1 em]-(2x-18)+7 &= 3x-15&& \\[1 em]-2x+18+7 &= 3x-15&& \\[1 em]-2x+25 &= 3x-15&& \text{move the $ \color{blue}{ 3x } $ to the left side and $ \color{blue}{ 25 }$ to the right} \\[1 em]-2x-3x &= -15-25&& \text{simplify left and right hand side} \\[1 em]-5x &= -40&& \text{ divide both sides by $ -5 $ } \\[1 em]x &= \frac{-40}{-5}&& \\[1 em]x &= 8&& \\[1 em] \end{aligned} $$

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