% variables
array[1..4] of var float: x;


% constraint ->COMPLETEZ ICI<-;
constraint x[1] + x[2] + x[3] + x[4] >= 2;
constraint 3*x[2] - x[3] >= 5;
constraint x[3] + x[4] >= 3; 
constraint x[4] <= 1;

% constraint forall(->COMPLETEZ ICI<-)(->COMPLETEZ ICI<-);
constraint forall (i in 1..4)(x[i] >= 0);

% var float: obj = ->COMPLETEZ ICI<-;
var float: obj = 2*x[1] + x[2] + 4*x[3] + x[4];

solve minimize obj;

output ["\n x1=\(x[1])\n x2=\(x[2])\n x3=\(x[3])\n x4=\(x[4])\n OBJ=\(obj)\n"];