Note: This is a goal programming problem, not a general linear programming problem.

(1) First, consider the constraint that the output of A is not greater than that of product B: x1+d1(-)-d1(+) = x2;

(2) Secondly, the constraint of not wanting to work overtime: x1+3x2+D2 (-)-D2 (+) =12;

(3) Finally, the profit should exceed 70: 9x1+12x2+D3 (-)-d1(+) = 70.

The objective function is minf = p1d1(+)+p2d2 (+)+p3d3 (-).

Here, D 1 (-), D 1 (+), D2 (-), D2 (+), D3 (-), D3 (+) >: = 0; P 1, P2, P3 represent 1, 2, 3 level targets respectively, which can be understood as P 1 P2 P3.