Answer:
Explanation:
Step 1: draw the lines corrisponding to the various equations (you get them by replacing the inequality sign with an equal, just pick two points, and draw a line between them).
Step 2, Check in which region of the plane the inequality is true. Pick an easy point (like, 0;0) and replace the coordinates in the equation. If you get something true, the half-plane including the origin is the area you need, else, it's on the other side. Pick a second point as it's required (i recommend 10;0, since it's easier to see).
As you replace 0;0, you get: 0>15 (obviously false), 5>0, false as well, and
, which is true.
As you replace 10;0 you get 30>15, true; 15>0, true, and
, false. The part of the plane you need is on the left of the intersection of the green and red line. Attached the solution - I tried to keep the color code of your photo.