$$ \begin{aligned} 31 &= 19+\frac{1}{4}a&& \text{multiply ALL terms by } \color{blue}{ 4 }. \\[1 em]4\cdot31 &= 4\cdot19+4 \cdot \frac{1}{4}a&& \text{cancel out the denominators} \\[1 em]124 &= 76+a&& \text{ swap the left and right side of the equation } \\[1 em]76+a &= 124&& \text{ move 76 to the right } \\[1 em]a &= 124-76&& \\[1 em]a &= 48&& \\[1 em]a &= 48&& \\[1 em] \end{aligned} $$

This page was created using