Answer:
12 x^4 + 18 x^3 - 9 x^2 thus D is the correct answer.
Explanation:
Expand the following:
3 x^2 (4 x^2 + 6 x - 3)
3 x^2 (4 x^2 + 6 x - 3) = 3 x^2 (4 x^2) + 3 x^2 (6 x) + 3 x^2 (-3):
3 4 x^2 x^2 + 3 6 x^2 x - 3 3 x^2
3 (-3) = -9:
3 4 x^2 x^2 + 3 6 x^2 x + -9 x^2
3 x^2×6 x = 3 x^(2 + 1)×6:
3 4 x^2 x^2 + 3×6 x^(2 + 1) - 9 x^2
2 + 1 = 3:
3 4 x^2 x^2 + 3 6 x^3 - 9 x^2
3×6 = 18:
3 4 x^2 x^2 + 18 x^3 - 9 x^2
3 x^2×4 x^2 = 3 x^4×4:
3×4 x^4 + 18 x^3 - 9 x^2
3×4 = 12:
Answer: 12 x^4 + 18 x^3 - 9 x^2