Answer:
4x³ + 12x²
Step-by-step explanation:
I assume the denominators are x² and 4x although that is not what you wrote.
x² = x² (already factored)
4x² + 12x = 4x(x + 3)
LCD = 4 × x² × (x + 3)
LCD = 4x³ + 12x²
