Answer:
C. 3x^3 + 2y
Explanation:
9x^6 + 12x^3y + 4y^2
9x^6 = (3x^3)^2
4y^2 = (2y)^2
So far it looks like the trinomial can be the square of a binomial. We need to check the middle term.
2 * 3x^3 * 2y = 12x^3y
The middle term checks out, so this trinomial is a perfect square trinomial.
9x^6 + 12x^3y + 4y^2 = (3x^3 + 2y)^2
Answer: C. 3x^3 + 2y