Answer:
(3x² + 2y)²
Step-by-step explanation:
Given
9[tex]x^{4}[/tex] + 12x²y + 4y² ← a perfect square
9[tex]x^{4}[/tex] = (3x²)² and 4y² = (2y)²
of the form
9[tex]x^{4}[/tex] + 12x²y + 4y² = (3x² + 2y)(3x² + 2y) = (3x² + 2y)²