[tex] \sqrt{72} \times \sqrt{ {x}^{3} } [/tex]
[tex] \sqrt{{3}^{2} \times {2}^{2} \times 2 } \times \sqrt{ {x}^{3} } [/tex]
[tex]3 \times 2 \times \sqrt{2} \times \sqrt{ {x}^{3} } [/tex]
[tex]6\sqrt{2} \times \sqrt{ {x}^{2} \times x } [/tex]
[tex]6 \sqrt{2} \times x \sqrt{x} [/tex]