$$ \begin{aligned} x-\frac{7}{4}+x+\frac{3}{20} &= 7&& \text{multiply ALL terms by } \color{blue}{ 20 }. \\[1 em]20x-20\cdot\frac{7}{4}+20x+20\cdot\frac{3}{20} &= 20\cdot7&& \text{cancel out the denominators} \\[1 em]20x-35+20x+3 &= 140&& \text{simplify left side} \\[1 em]40x-32 &= 140&& \text{ move -32 to the right } \\[1 em]40x &= 140+32&& \\[1 em]40x &= 172&& \text{ divide both sides by $ 40 $ } \\[1 em]x &= \frac{172}{40}&& \\[1 em]x &= \frac{43}{10}&& \\[1 em] \end{aligned} $$

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