Incorrect. Remember that $\displaystyle{{5}}^{{x}}{{5}}^{{y}}={{5}}^{{{x}+{y}}}\usepackage{cmbright}\Huge\$ and $\displaystyle{{\left({{5}}^{{a}}\right)}}^{{b}}={{5}}^{{{a}{b}}}\usepackage{cmbright}\Huge\$ . You can rewrite $\displaystyle{{\left(-{1}\right)}}^{{6}}{\left({{5}}^{{-{{2}}}}\right)}{{\left({{5}}^{{-{{4}}}}\right)}}^{{-{{3}}}}\usepackage{cmbright}\Huge\$ as $\displaystyle{\left({1}\right)}{\left({{5}}^{{-{{2}}}}\right)}{\left({{5}}^{{-{4}\cdot{\left(-{3}\right)}}}\right)}\usepackage{cmbright}\Huge\$ ; does this help you solve the problem?