Answer
$(-2,-1]$
Work Step by Step
Step 1. Graph $R(x)=\frac{3x+3}{2x+4}$ as shown in the figure.
Step 2. The vertical asymptote ($x=-2$) and a zero ($x=-1$) divide the x-axis into three intervals $(-\infty,-2),(-2,-1],[-1,\infty)$
Step 3. For $R(x)\le0$, we can identify the solution intervals as $(-2,-1]$