In the given figure, we see that $OC$ line
passing through (0,0) and (3,3) .
$\therefore $ Equation of line is $y=x$
Also, we see that shaded portion of this line is towards the $X$ -axis, so we take $x-y \geq 0$.
In the figure, line $AB$ is parallel to $Y$ -axis.
$\therefore $ Equation of line $AB$ is $x=5$, also shaded portion of this line is towards the origin, so we take $x-5 \leq 0$ or $x \leq 5$
In the figure, line $BC$ is parallel to $X$ -axis
$\therefore $ Equation of line $BC$ is $y=3$. Also, shaded
portion of this line is towards the origin, so we take $y-3 \leq 0$ or $y \leq 3$
Also, the shaded region lies in first quadrant, so $x \geq 0$ and $y \geq 0$
Hence, constraints of given shaded region are
$x, y \geq 0, x-y \geq 0, x \leq 5, y \leq 3$
