Which expressions are completely factored?

Choose all answers that are correct.

Question 4 options:

18x^4 – 12x^2 = 6x(3x^3 – 2x)


12x^5 + 8x^3 = 2x^3(6x^2 + 4)


20x^3 + 12x^2 = 4x^2(5x + 3)


24x^6 – 18x^5 = 6x^5(4x – 3)