Answer
The region includes all the points that are above the line $y = -x$ and below the line $y = \frac{1}{2}(x+3)$
Note that the points on the line $y = -x$ are also included in the region, but the points on the line $y = \frac{1}{2}(x+3)$ are not included in the region.
Work Step by Step
$\{(x,y)\vert~-x \leq y \lt \frac{1}{2}(x+3) ~\}$
The region includes all the points that are above the line $y = -x$ and below the line $y = \frac{1}{2}(x+3)$
Note that the points on the line $y = -x$ are also included in the region, but the points on the line $y = \frac{1}{2}(x+3)$ are not included in the region.
