$$ \begin{aligned} 12 &= -\frac{x}{4}+x&& \text{multiply ALL terms by } \color{blue}{ 4 }. \\[1 em]4\cdot12 &= -4 \cdot \frac{x}{4}+4x&& \text{cancel out the denominators} \\[1 em]48 &= -x+4x&& \text{simplify right side} \\[1 em]48 &= 3x&& \text{ swap the left and right side of the equation } \\[1 em]3x &= 48&& \text{ divide both sides by $ 3 $ } \\[1 em]x &= \frac{48}{3}&& \\[1 em]x &= 16&& \\[1 em] \end{aligned} $$

This page was created using