The x and y intercepts for are located at (a,0) and (0,b) respectively.
Note that 'a' and 'b' must be nonzero.
So something like has its x and y intercepts at (30,0) and (0,40).
Draw a straight line through those two points.
This boundary line is solid because of the "or equal to" in the inequality sign.
Shade below the boundary due to the "less than" part.
Or you can use a test point like (0,0) to try out.
Follow this idea for the other inequalities as well. Then pay careful attention where the three regions overlap.
That overlapped region has corner vertex points that will be plugged into the objective function
I'll let the student take over from here.
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