# How do you simplify x/3 - x/7?

$\frac{x \times 7}{3 \times 7} - \frac{x \times 3}{7 \times 3}$
$\frac{7 x}{21} - \frac{3 x}{21}$
$\frac{7 x - 3 x}{21}$
$\frac{4 x}{21}$