Correct. $\displaystyle\sqrt{{{18}{{a}}^{{5}}{{b}}^{{8}}}}=\sqrt{{{9}\cdot{2}\cdot{{a}}^{{4}}\cdot{a}\cdot{{b}}^{{8}}}}\usepackage{cmbright}\Huge\$ ; factoring out the squared quantities results in the simplified expression $\displaystyle\sqrt{{{{3}}^{{2}}\cdot{2}\cdot{{\left({{a}}^{{2}}\right)}}^{{2}}\cdot{a}\cdot{{\left({{b}}^{{4}}\right)}}^{{2}}}}={3}{{a}}^{{2}}{{b}}^{{4}}\sqrt{{{2}{a}}}\usepackage{cmbright}\Huge\$ .