# How do you find the LCD for 9/(k+3) and 3/k?

Since $k + 3$ and $k$ have no common factors:
$\textcolor{w h i t e}{\text{XXXX}}$the Least Common Denominator of
$\textcolor{w h i t e}{\text{XXXX}}$$\textcolor{w h i t e}{\text{XXXX}}$$\frac{9}{k + 3}$ and $\frac{3}{k}$
$\textcolor{w h i t e}{\text{XXXX}}$is
$\textcolor{w h i t e}{\text{XXXX}}$$\textcolor{w h i t e}{\text{XXXX}}$$\left(k\right) \left(k + 3\right) = {k}^{2} + 3 k$