Step-by-step explanation:
[tex] \sqrt{128 {x}^{8} {y}^{3} {z}^{9} } \\ \\ = \sqrt{64 \times 2 {x}^{8} \times {y}^{2} \times y{z}^{8} \times z} \\ \\ = \sqrt{ {(8)}^{2} \times 2 \times ( {x}^{4})^{2} \times {y}^{2} \times y \times( {z}^{4})^{2} \times z} \\ \\ = 8 {x}^{4} y {z}^{4} \sqrt{2 \times y \times z} \\ \\ = 8 {x}^{4} y {z}^{4} \sqrt{2 y z} [/tex]
