# How do you factor completely 225h^2-1?

$\left(15 h - 1\right) \left(15 h + 1\right)$
$225 {h}^{2} - 1$ = ${\left(15 h\right)}^{2} - {\left(1\right)}^{2}$ = $\left(15 h - 1\right) \left(15 h + 1\right)$