1. The problem asks to identify points where the graph is not differentiable. 2. A graph is not differentiable at points where it has sharp corners, cusps, discontinuities, or vertical tangents. 3. From the description: - The graph is linear from (-4,1) to (-1,3) with a peak at (-3,4). A peak indicates a sharp corner, so the graph is not differentiable at $x=-3$. - From (-1,3) to (1,2), the graph is linear but has an open circle at $x=1$ indicating a discontinuity, so it is not differentiable at $x=1$. - The graph continues smoothly to (3,2) then falls sharply, indicating a sharp corner or cusp at $x=3$, so it is not differentiable there. 4. Points $x=-2$ and others are on linear segments without sharp corners or discontinuities, so the graph is differentiable there. 5. Therefore, the points where the graph is not differentiable are $x=-3$, $x=1$, and $x=3$. Final answer: The graph is not differentiable at $x=-3$, $x=1$, and $x=3$.