Brainliest for whoever gets this correct! What is the least common denominator of the rational expressions below?

3x³(x + 5)

Step-by-step explanation:

1/x² - 4/(3x² + 15x)

Factor 3x² + 15x.

3x² + 15x

3x(x + 5)

Find the least common denominator.

(1 × 3x(x + 5))/(x² × 3x(x + 5)) - (4 × x²)/(3x² + 15x × x²)

(3x(x + 5))/(3x³(x + 5)) - (4x²)/(3x³(x + 5))

The least common denominator is 3x³(x + 5).