Question

How to plot inequalities `x+2y≥4`?

Answer 1

Determine any two points on the line of the equation `x+2y=4`

(I chose the x and y intercepts `(0,2)` and `(4,0` as being easy to evaluate).

Draw a straight line that goes through those two points.

For `x+2y >= 4` the solution points are on and above this line.