Answer:
[tex](9x^3y^2)^2[/tex]
Step-by-step explanation:
The expression, as a square of a monomial, will be given by:
[tex](\sqrt{81x^6y^4})^2[/tex]
Now, we calculate the root, applying it's properties. So
[tex]\sqrt{81x^6y^4} = \sqrt{81} \times \sqrt{x^6} \times \sqrt{y^4} = 9 \times x^{\frac{6}{2}} \times y^{\frac{4}{2}} = 9x^3y^2[/tex]
The expression as a square of a monomial is given by
[tex](9x^3y^2)^2[/tex]