Answer:
B. [tex] 60x^8 [/tex]
Step-by-step explanation:
[tex] 4x^2\sqrt{5x^4} \cdot 3\sqrt{5x^8} = [/tex]
[tex] = 4x^2 \times 3 \sqrt{5x^4 \times 5x^8} [/tex]
[tex] = 12x^2 \sqrt{25x^{4+8}} [/tex]
[tex] = 12x^2 \sqrt{25} \sqrt{x^{12}} [/tex]
[tex] = 12x^2 \times 5 \times x^6 [/tex]
[tex] = 60x^8 [/tex]
