Hello from MrBillDoesMath!
Answer: 3x^3 + 6 x^2 - 12 x (the third choice)
Discussion:
(x^2 + 2x -4) * (3x) =
x^2 (3x) + 2x (3x) -4 (3x) =
3x^3 + 6 x^2 - 12 x
which is the third choice
Thank you,
MrB
