Consider the following equation:

$\displaystyle-{12}{{x}}^{{7}}{\left({5}{{x}}^{{5}}+{6}{x}-{9}{{x}}^{{3}}\right)}=-{60}{{x}}^{{{12}}}-{72}{{x}}^{{8}}\usepackage{cmbright}\Huge\$ ____

Fill in the blank with the correct term, and be sure to include a positive or negative sign in your answer.

Note: Write exponents by using the ^ key. For example, $\displaystyle{{x}}^{{2}}\usepackage{cmbright}\Huge\$ can be recorded as x^2, and $\displaystyle{5}{{x}}^{{3}}\usepackage{cmbright}\Huge\$ can be recorded as 5x^3.