$$ \begin{aligned} 12k-4 &= 8(k+3)&& \text{simplify right side} \\[1 em]12k-4 &= 8k+24&& \text{move the $ \color{blue}{ 8k } $ to the left side and $ \color{blue}{ -4 }$ to the right} \\[1 em]12k-8k &= 24+4&& \text{simplify left and right hand side} \\[1 em]4k &= 28&& \text{ divide both sides by $ 4 $ } \\[1 em]k &= \frac{28}{4}&& \\[1 em]k &= 7&& \\[1 em] \end{aligned} $$

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