<s>[INST] $a/b=c$, how to move the numerator to the right side of the equation Given an equation of the form $a/b=c$, how do you move $a$, the numerator, over to the other side so that you get $b =c?$ (where $?$ denotes my ignorance of what the right side should look like).
 [/INST] $$
\begin{align}
\frac{a}{b} & = c \\ \\
b \cdot \frac{a}{b} & = c \cdot b \\
\require{cancel} \\
\cancel{b} \cdot \frac{a}{\cancel{b}} & = c \cdot b \\ \\
a & = cb \\ \\
\frac{a}{c} & = \frac{cb}{c} \\ \\
\frac{a}{c} & = \frac{\cancel{c}b}{\cancel{c}} \\ \\
\frac{a}{c} & = b
\end{align}
$$
</s>