PLEASE SHOW ME THE FOLLOWING GRAPHS WITH THE SHADED PORTION :

1) x=0 [ x is greater than or equal to zero ]

2) y=0 [ y is greater than or equal to zero ]

3) x=0 , y=0 [x is greater than or equal to zero , y is greater than or equal to zero]

1)
$Region for x\ge 0$ 
As we know that x =0 is nothing but y axis and if we are asked for x greater than or equal to 0 then, 
it will be right to y- axis and this region can be shown as, 
 
Here the shaded portion is the required portion.
2)
For y$\ge 0$, 
as we know that y =0 is x -axis so y greater than or equal to zero will be a region above x axis and can be given as, 

3)
for the region x$\ge 0 \mathrm{and} \mathrm{y}\ge 0$, 
Now this is nothing but intersection of first part and second part and we can see that x and y are both positive in first quadrant and so is the intersection of first part and second part,