The product rule says $\displaystyle{{x}}^{{a}}\cdot{{x}}^{{b}}={{x}}^{{{a}+{b}}}\usepackage{cmbright}\Huge\$ , so $\displaystyle{{3}}^{{2}}\cdot{{3}}^{{8}}={{3}}^{{{2}+{8}}}\usepackage{cmbright}\Huge\$ .