Question 892441
First graph the feasible region.
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{{{drawing(300,300,-6,6,-6,6,grid(1),blue(line(2,-20,2,20)),circle(2,5,0.2),circle(2,0,0.2),blue(line(-10,5,10,5)),graph(300,300,-6,6,-6,6,x-4))}}}
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The feasible region is simplified to {{{x<=2}}} and {{{0<=y<=5}}} and the line {{{x-y<=4}}} does not contribute any constraint. 
Since there is no minimum value for {{{x}}}, there is no minimum value for {{{p}}}.
The maximum value occurs at one of the two vertices.
(2,0):{{{p=2+4(0)=2}}}
(2,5):{{{p=2+4(5)=2+20=22}}}