a =[85 60 120 80 120； 80 150 90 160 60; 100 120 150 120 100];

b =[75； 120; 138];

Lb = zero (5,1);

[x，fval，exitflag，output，lambda] = linprog(f，A，b，[]，[]，lb)

Answer:

fval =

1.4727e-0 14

x =

1.0e-0 14 *

0.3975

0.0782

0. 1976

0. 17 14

0. 1285

What is D in the title is unclear.