Complete the factorization of $\displaystyle{36}{{x}}^{{2}}+{12}{x}+{1}\usepackage{cmbright}\Huge\$ by supplying the missing value.

$\displaystyle{36}{{x}}^{{2}}+{12}{x}+{1}={{\left(?{x}+{1}\right)}}^{{2}}\usepackage{cmbright}\Huge\$