$$ \begin{aligned} 3(x+5) &= \frac{30}{5}&& \text{multiply ALL terms by } \color{blue}{ 5 }. \\[1 em]5\cdot3(x+5) &= 5\cdot\frac{30}{5}&& \text{cancel out the denominators} \\[1 em]15x+75 &= 30&& \text{ move 75 to the right } \\[1 em]15x &= 30-75&& \\[1 em]15x &= -45&& \text{ divide both sides by $ 15 $ } \\[1 em]x &= -\frac{45}{15}&& \\[1 em]x &= -3&& \\[1 em] \end{aligned} $$

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