Question

Graph the inequality on a plane

Answer 1

\[x+y \le3\]

Answer 2

First graph the line x+y=3. Now choose a point which lies on one side of the line, (say above the line) and look at x+y for that point. If x+y is less than 3 at that point then you can deduce that ALL the points above the line also satisfy the inequality, and so the region is above the line. If the value of x+y at the chosen point is bigger than three, then the points satisfying the inequality will all lie below the line.