param N := 4;

var x{1..N};

minimize f:
-0.5*x[1] - x[2] - 0.5*x[3] - x[4];

subject to cons1:
10 - x[1] - x[2] - x[3] - x[4] >= 0;

subject to cons2:
10 - 0.2*x[1] - 0.5*x[2] - x[3] - 2*x[4] >= 0;

subject to cons3:
10 - 2*x[1] - x[2] - 0.5*x[3] - 0.2*x[4] >= 0;

subject to cons4:
x[1] + x[2] + x[3] - 2*x[4] - 6 = 0;

subject to cons5{i in 1..N}:
x[i] >= 0;


data;
var x:=
1	1
2	1
3	1
4	1;

solve;

display x;