Add 4 to both sides, and then divide by 4:

$\displaystyle{4}{t}-{4}+{4}>{16}+{4}\usepackage{cmbright}\Huge\$ or $\displaystyle{4}{t}>{20}\usepackage{cmbright}\Huge\$

$\displaystyle\frac{{{4}{t}}}{{4}}>\frac{{20}}{{4}}\usepackage{cmbright}\Huge\$ or $\displaystyle{t}>{5}\usepackage{cmbright}\Huge\$