Step 1:

The first inequality is $x+y \leq 9 $----(1)

Consider the equation $x +y =9$

The points (9,0) and (0,9) satisfy the equation.

The graph of the line is drawn as shown.

The line divides the xy -plane into two half planes .

Consider the point (0,0) We see that

$0+0 \leq 9$

$0 \leq 9$ is true.

Thus the inequality $x+y \leq 9$ represents the region below the line $x+y =9$ containing the point (0,0) including the line .

Step 2:

The second inequality $ y > x$ ----(2)

consider the equation $y=x$

The points $(1,1) ,(0,0)$ satisfy the equation.

The graph of the line $y=x$ is drawn using dotted line as shown .

The graph divides the xy plane into two half planes.

consider the point $(1,0) $ we see that

$ 0 > 1$ is false.

Thus the region represented by the inequality $y >x$ is above the line not containing point (1,0) (excluding the line y=x)

Step 3:

The third inequality $x \geq 0$

The inequality represents the region right of the y-axis (including y axis )

Step 4:

The solution of the system of inequality is represented by the common shaded region including the points on the line $x+y =9$ and $x=0$ and excluding the points on the line $y=x$.