用lingo求解程序，线性规划。只需要结果就行（身边没有lingo软件）

结果为x1=5，x2=0，Smin=150

代码及运行结果如下：

min=30*x1+40*x2;
x1+x2>5;
5*x1-5*x2>2;
2*x1-6*x2>3;

  Global optimal solution found.
  Objective value:                              150.0000
  Infeasibilities:                              0.000000
  Total solver iterations:                             1


                       Variable           Value        Reduced Cost
                             X1        5.000000            0.000000
                             X2        0.000000            10.00000

                            Row    Slack or Surplus      Dual Price
                              1        150.0000           -1.000000
                              2        0.000000           -30.00000
                              3        23.00000            0.000000
                              4        7.000000            0.000000