Answer:
(9x²)²
Explanation:
Given the expression 81x⁴, to write the expression as a square of a monomial, first we will assign a variable to the expression.
y = 81x⁴
Then we take the square root of both sides of the expression
√y = √81x⁴
y^½ = √81 × √x⁴
y^½ = 9x²
Squaring both sides of the resulting equation to get y back
(y^½)² = (9x²)²
y = (9x²)²
The expression as a square of a monomial is (9x²)²