Simplify using the multiplication rule.

[tex]\sf \bf {\boxed {\mathbb { a. \:2 {y}^{2} \sqrt{6x}}}}[/tex]
[tex]\large\mathfrak{{\pmb{\underline{\red{Step-by-step\:explanation}}{\red{:}}}}}[/tex]
[tex] \sqrt{4x {y}^{3} } \sqrt{6y} [/tex]
[tex] = \sqrt{4 \times 6 \: x \: {y}^{(3 + 1)} } [/tex]
[tex] = \sqrt{( {2})^{2} \times 6 \: x \: {y}^{4} } [/tex]
[tex] = \sqrt{( {2})^{2} \times 6 \: x \: { ({y}^{2} })^{2} } [/tex]
[tex] = 2 {y}^{2} \sqrt{6x} [/tex]
[tex]\large\mathfrak{{\pmb{\underline{\orange{Mystique35 }}{\orange{❦}}}}}[/tex]