The given expression is :
[tex]\sqrt[]{y^3}+\sqrt[]{9y^3}-3y\sqrt[]{y}[/tex]as the square root is express as :
[tex]\sqrt[]{a^2}=a[/tex]Simplify the expression :
[tex]\begin{gathered} \sqrt[]{y^3}+\sqrt[]{9y^3}-3y\sqrt[]{y}=\sqrt[]{y^2\times y}+\sqrt[]{3^2y\times y^2}-3y\sqrt[]{y} \\ \sqrt[]{y^3}+\sqrt[]{9y^3}-3y\sqrt[]{y}=y\sqrt[]{y}+3y\sqrt[]{y}-3y\sqrt[]{y} \\ \sqrt[]{y^3}+\sqrt[]{9y^3}-3y\sqrt[]{y}=y\sqrt[]{y} \end{gathered}[/tex]Answer : A)
[tex]y\sqrt[]{y}[/tex]
