How do you solve for x in x/r = v?

$x = r v$

Explanation:

We start from the given $\frac{x}{r} = v$

$\frac{x}{r} = v$
Multiply both sides by $r$

$r \cdot \frac{x}{r} = r \cdot v$

$\cancel{r} \cdot \frac{x}{\cancel{r}} = r \cdot v$

$x = r \cdot v$

God bless....I hope the explanation is useful.