$$ \begin{aligned} 28-\frac{4}{2}x\cdot10 &= 20&& \text{multiply ALL terms by } \color{blue}{ 2 }. \\[1 em]2\cdot28-2 \cdot \frac{4}{2}x\cdot10 &= 2\cdot20&& \text{cancel out the denominators} \\[1 em]56-40x &= 40&& \text{ move 56 to the right } \\[1 em]-40x &= 40-56&& \\[1 em]-40x &= -16&& \text{ divide both sides by $ -40 $ } \\[1 em]x &= \frac{-16}{-40}&& \\[1 em]x &= \frac{2}{5}&& \\[1 em] \end{aligned} $$

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