Answer
if the denominators use the same factor, but with different exponents.
Work Step by Step
The $LCD$ of two rational expressions with different denominators is equal to one of the denominators if the denominators use the same factor, but with different exponents. For example, the $LCD$ of $\dfrac{3x}{x+2}$ and $\dfrac{7x+1}{(x+2)^3}$ is $(x+2)^3$ since both denominators use the same factor, but with different exponents.
